Grafted kalata b1 cyclotides and their chemical synthesis approach

Abstract

The present invention relates to a grafted cyclotide comprising a cyclic cystine knot (CCK) derived from kalata B1 (kB1) and an amino acid sequence derived from dynorphin A (dynA sequence) grafted into the the inter-cysteine loop 3, 5 or 6 of said CCK. The present invention further relates to a pharmaceutical composition comprising the grafted cyclotide according to the invention. The present invention further relates to the grafted cyclotide or the pharmaceutical composition according to the invention for use in the treatment, amelioration or prophylaxis of a KOR-related disease, in particular of a disease resulting from or coming along with a decreased KOR activity and / or which is treatable by KOR agonism / an increased KOR activity. The present invention further relates to a method of preparing the grafted cyclotide according to the invention, namely the 'plug and play' synthesis approach of the invention. The present invention also relates to 'plug and play'-produced kB1-derived grafted cyclotides with loop 3-, loop 5- or loop 6- inserted dynA-derived grafts. The present invention further relates to the the disclosed kB1-derived acyclic grafting scaffold; as well as to the (linear) (kB1-derived) peptide backbone as comprised therein.

Description

[0001] New PCT Patent Application Medizinische Universität Wien; The University of Queensland Vossius Ref.: AJ1533 PCT S3 Grafted kalata B1 cyclotides and their chemical synthesis approach The present invention relates to a grafted cyclotide comprising a cyclic cystine knot (CCK) derived from kalata B1 (kB1) and an amino acid sequence derived from dynorphin A (dynA sequence) grafted into the the inter-cysteine loop 3, 5 or 6 of said CCK (loop 3, loop 5 or loop 6, respectively). The present invention also relates to a pharmaceutical composition comprising the grafted cyclotide according to the invention. The present invention further relates to the grafted cyclotide or the pharmaceutical composition according to the invention for use in the treatment, amelioration or prophylaxis of a KOR-related disease, in particular of a disease resulting from or coming along with a decreased KOR activity and / or which is treatable by KOR agonism / an increased KOR activity. The present invention further relates to a method of preparing the grafted cyclotide according to the invention (also termed herein the ‘plug and play’ synthesis approach of the invention). In the context of this synthesis approach, the six conserved C residues of a linear kB1-derived peptide backbone are, first, allowed to form the three disulfide-bridges to fold into a cystine knot (CK) motif (the grafting scaffold), and the dynA sequence (the graft) is grafted onto this grafting scaffold post-folding (resulting in a grafted kB1- derived cyclotide with the graft inserted into loop 3, loop 5 or loop 6 of the CCK). The present invention also relates to a kB1-derived grafted cyclotide with a loop 3-, loop 5-, or loop 6- inserted dynA-derived graft, wherein said grafted cyclotide has been produced by the (‘plug and play’) synthesis approach as disclosed herein. The invention further relates to the the herein disclosed (kB1-derived) (acyclic) grafting scaffold (comprising the folded CK motif); as well as to the (linear) (kB1-derived) peptide backbone as comprised therein (unfolded). Over the last few decades, peptides have attracted increased interest for drug discovery and development approaches (Muttenthaler, Nat. Rev. Drug Discov. 20, 2021, 309-25; Muratspahic, Trends Pharmacol. Sci. 40, 2019, 309-26; Lau, Bioorg. Med. Chem. 26, 2018, 2700-7). Peptides, in principle, can fill the gap between larger protein-type therapeutics and traditional small molecules, but their use is still limited by challenges such as their typically low metabolic stability (see, for example, Craik, Chem. Biol. Drug Des. 81, 2013, 136-47). Therefore, there is great interest in the stabilization of bioactive peptides via insertion / grafting into stable scaffolds, in particular into macrocyclic disulfide bridges-rich peptides (Wang, Nat. Chem. Biol.14, 2018, 417-27). Cyclotides, a diverse and versatile family of plant-derived cyclic mini-proteins, have emerged as such an attractive scaffolds. Cyclotides are characterized by a unique combination of a head-to-tail cyclic backbone and three intertwined disulfide-bridges that form a motif known as the cyclic cystine knot (CCK; Craik, J. Mol. Biol. 294, 1999, 1327-36). Their tightly packed three-dimensional structures exhibit remarkable structural stability and resistance against chemical, thermal or enzymatical / proteolytic degradation (Colgrave, Biochemistry 43, 2004, 5965-75). The use of cyclotides as grafting scaffolds can therefore lead to improved pharmacokinetics and, for example, oral activity, as well as selectivity and high enzymatic stability of the resulting grafted cyclotides (also sometimes termed “cyclotide analogues”). Thus, cyclotides have emerged as powerful scaffold molecules for designing peptide-based therapeutics. For example, the chemical engineering of cyclotides has generated grafted cyclotides as novel peptide ligands of the kappa opioid receptor (KOR) and of other G protein- coupled receptors (GPCRs), today’s most exploited drug targets. KOR ligands were also co- administered with non-grafted cyclotides (WO2021 / 186035); and the endogenous KOR ligand, dynorphin A (1-13), has also been grafted onto the cyclic (but non-cyclotide-derived) SFTI scaffold (Muratspahić, J. Med. Chem.64, 2021, 9042-55). Importantly, the prototypical cyclotide, kalata B1 (kB1), the prototypical cyclotide, is amenable to a range of single amino acid mutations (Simonsen, J. Biol. Chem.283, 2008, 9805- 13; Huang, J. Biol. Chem.285, 2010, 10797-805), but it can also accommodate insertions of so- called bioactive epitopes (grafts) into one or more of its inter-cysteine loops (Craik, Curr. Opin. Chem. Biol.38, 2017, 8-16; D'Souza, Biochemistry 55, 2016, 396-405; Wang, ACS Chem. Biol. 9, 2014, 156-63; Ji, J. Am. Chem. Soc.135, 2013, 11623-33; Lesniak, Chemistry 23, 2017, 14469- 75; Gao, Bioorg. Med. Chem.18, 2010, 1331-6; Getz, ACS Chem. Biol.6, 2011, 837-44). Epitope sequences (grafts) of up to 21 amino acids have been reported and resulting engineered cyclotides potently engage with a range of molecular targets (Craik, Curr. Opin. Chem. Biol.38, 2017, 8-16). In particular, there are several examples of grafted cyclotides that target GPCRs including KOR (Lesniak, Chemistry 23, 2017, 14469-75; Wong, Angew. Chem. Int. Ed. Engl.51, 2012, 5620-4; Eliasen, J. Biol. Chem.287, 2012, 40493-501; Aboye, Molecules 21, 2016, 152; Muratspahić, RSC Chem. Biol. 1, 2020, 177-91), one of the major (classes of) drug target(s). Dürrauer (Masters’ Thesis, Universität Wien, 2018, Characterisation of Novel Drug Leads for Multiple Sclerosis; https: / / ubdata.univie.ac.at / AC15193354) attempted to graft dynorphin A (1-13) and a fragment of dynorphin A (1-13), dynorphin A (1-8), into a scaffold which derived from the particular kB1 mutant [T20K]kB1. In planta, cyclotides are ribosomally synthesized (Jennings, Proc Natl Acad Sci U S A 98, 2001, 10614-9), but they can be produced via a variety of chemical strategies (or recombinant strategies). Predominantly, (grafted) cyclotides are synthesized by using Fmoc-based SPPS approaches (Tam, Tetrahedron Lett.38, 1997, 5599-602; Daly, Biochemistry 38, 1999, 10606- 14; Clark, Biochem. J.394, 2006, 85-93; Thongyoo, Chem. Commun. (Camb), 2006, 2848-50; Zheng, Chembiochem 13, 2012, 542-6; Gunasekera, Int. J. Pept. Res. Ther. 19, 2013, 43-54). One of the most commonly applied synthesis protocols for (grafted) cyclotides is the assembly of the peptide chain on a highly acid-labile resin to yield a fully side-chain protected peptide upon low-TFA cleavage of the peptide chain from the solid support. Backbone cyclization is achieved via in-solution ligation with standard coupling conditions using HATU / DIPEA (Cheneval, J. Org. Chem.79, 2014, 5538-44). The crude (grafted) cyclic peptide then undergoes side-chain deprotection prior to purification. Subsequent oxidative folding and another round of purification finally affords the desired product, i.e. the (grafted) cyclotide (cf. Fig.1A). However, cyclotide synthesis, in particular grafted cyclotide synthesis, remains a major bottleneck and limits the widespread use of cyclotides, in particular in a pharmaceutical context. Although recent improvements in automated SPPS may have facilitated the assembly also of so-called ‘problematic’ peptide sequences (Collins, Org. Lett.16, 2014, 940-3), access to grafted peptides by stepwise SPPS can be inefficient, resulting in low yields of crude peptides. More importantly, the folding of cyclotides which already contain bioactive epitopes (the grafts) remains a predominant bottleneck in grafted cyclotide synthesis. In particular, oxidative folding of grafted cyclotides is often significantly impaired due to the inserted sequence causing structural perturbation that does not allow the formation of the native CCK fold (Simonsen, J. Biol. Chem. 283, 2008, 9805-13; Huang, J. Biol. Chem. 285, 2010, 10797- 805). This affects yield and feasibility of cyclotide grafting via traditional SPPS protocols (cf. Fig.1A). There is thus still an unmet need in the field of grafted cyclotide synthesis and applications, namely the need to overcome the impaired folding of the CCK motif in the context of recent cyclotide grafting approaches, and the resulting unsatisfactory / insufficient low yields of the grafted cyclotides, respectively. The problem underlying the present invention is therefore the provision of means and methods for an efficient synthesis of grafted cyclotides (in particular of stable and pharmaceutically active grafted cyclotides), e.g. with satisfactory / sufficient yields. The technical problem is solved by the provision of the embodiments characterized in the claims. The present invention solves the technical problem because, as documented herein below and in the appended examples, a modular chemical synthesis approach for grafted cyclotides (also termed ‘plug and play’ approach herein), and respective grafting scaffolds and peptide backbones, has / have been established in the context of the invention. A core aspect of the ‘plug and play’ approach of the invention is that biologically active epitopes (the grafts) are grafted onto an already folded, but yet acyclic, cyclotide-like scaffold (the grafting scaffold; cystine knot (CK)) (cf. Fig. 1B). It has further been shown in the context of this invention that a grafting scaffold (pre-folded, but yet acyclic) which derives from kB1 as the basis cyclotide is particularly useful in the ‘plug and play’ approach of the invention. Surprisingly, a kB1-derived grafting scaffold (pre-folded, but yet acyclic) having the site for inserting the graft in the inter-cysteine loop 3, 5 or 6 of the CCK (termed also just loop 3, loop 5 or loop 6, respectively) was shown to be highly suitable. Event more surprisingly, when a kB1-derived grafting scaffold with an amino acid substitution corresponding to a Glu->Gln replacement (E3Q) at position 3 of the basis cyclotide kB1 (SEQ ID No: 1) (corresponding to amino acid position 2 of loop 1) was used in the ‘plug and play’ approach of the invention, major side-products were largely abolished and yields of the final (cyclic / cyclized) grafted cyclotide were significantly increased (cf. Fig.2). The ‘plug and play’ approach of the invention, and the kB1-derived grafting scaffold and respective peptide backbone, circumvent two major bottlenecks of grafted cyclotide synthesis, namely (i) the stepwise assembly of longer and thus more difficult / complex sequences; and, more importantly, (ii) the problems associated with the (oxidative) folding of already grafted peptides, i.e. of already cyclic / cyclized peptide backbones comprising both, the amino acid sequences of the cyclotide part and of the graft part (cf. Fig.1A). In the context of the invention, the usefulness of the ‘plug and play’ approach, and the kB1- derived grafting scaffold and respective peptide backbone, for the efficient production / synthesis of pharmaceutically active grafted cyclotides was also shown. In this context, and as the respective proof-of-principle, the amino acid sequence derived from the endogenous κ- opioid receptor ligand dynorphin A (1-13) (also referred to herein “dynA sequence”) was grafted onto the kB1-derived grafting scaffold of the invention; with the site for inserting the graft in loop 3, loop 5 or loop 6 (^L3, ^L5, ^L6, respectively). The resulting kB1-dynA grafted cyclotides were shown to target the GPCR, KOR, with nanomolar affinities and potencies. Accordingly, also a peptide that could previously not be accessed for kB1-based grafting by using currently established protocols (Zheng, Chembiochem 13, 2012, 542-6; Cheneval, J. Org. Chem.79, 2014, 5538-44) was now successfully grafted into a kB1-derived cyclotide scaffold; and respective grafted cyclotides can now easily be obtained by applying the ‘plug and play’ approach of the invention. Thus, the present invention further provides for the proof-of-concept that also difficult-to-graft sequences can be easily obtained by the ‘plug and play’ approach of the present invention. This approach also allows for grafting complex epitopes, including sequences containing additional disulfide bonds or non-standard amino acids, into (different loops of) a cyclotide scaffold. In summary, a convenient and robust approach to rapidly access a structurally diverse range of grafted cyclotides that circumvents the problems associated with the (oxidative) folding of non- native CCK peptides has been established in the context of the invention. This approach allows a reliable insertion of structurally diverse grafts into the the provided grafting scaffold, and thus the efficient / rapid diversification of this scaffold to efficiently / rapidly achieve the respective diverse grafted cyclotides. Thus, the ‘plug and play’ approach of the invention unlocks the potential of cyclotides in drug design applications for a variety of pharmaceutically relevant targets. In one aspect, the present invention relates to a kB1-derived grafted cyclotide (folded, cyclic; including the amino acid sequence (peptide backbone) of the respective grafting scaffold and of the respective graft; including the CCK as derived from kB1). The present invention further relates to the respective grafting scaffold (folded; but acyclic; including the amino acid sequence (peptide backbone) of the respective grafting scaffold (without the graft); including the acyclic cystine knot (CK) as derived from kB1). The present invention further relates to the peptide backbone as comprised in the grafted cyclotide (cyclic or linear / acyclic; unfolded; including the amino acid sequence of the respective grafting scaffold and of the graft). The invention further relates to the peptide backbone as comprised in the grafting scaffold (linear / acyclic; unfolded; not including the amino acid sequence of the graft). The kB1-derived grafted cyclotide of the invention comprises (I) a CCK derived from kB1 (kB1 is depicted in SEQ ID NO: 1); and (II) an amino acid sequence derived from dynorphin A (1-13) (also termed herein “dynA sequence”; dynorphin A (1-13) (sometimes also termed just “dynorphin A” or “dynA”) is depicted in SEQ ID NO:36), wherein said dynA sequence is comprised in (i) the inter-cysteine loop 3 of said CCK (loop 3); (ii) the inter-cysteine loop 5 of said CCK (loop 5); or (iii) the inter-cysteine loop 6 of said CCK (loop 6). The meanings of the terms “cyclotide”, “grafted cyclotide”, “grafting scaffold” (also known as (engineering) framework; Craik 1999), “graft”, “CCK”, “CK” as well of “kB1” and “dynorphin A” are well known in the art and (if not explicitly stated otherwise) are used accordingly herein and in the context of the invention. A “cyclotide” is (or comprises) a head-to-tail cyclic peptide backbone, which amino acid chain includes six conserved cysteine residue (CI-CVI) forming three intertwined disulfide bridges (CI with CIV; CIIwith CV; CIIIwith CVI) that form a motif known as CCK motive (see, for example, Craik, J. Mol. Biol 294, 1999, 1327-36; US-A1 2010 / 0298528). The amino acid sequence stretches between the six cysteine residues are termed inter-cysteine loop 1 (of said CCK) (loop 1; between CIand CII), inter-cysteine loop 2 (of said CCK) (loop 2; between CIIand CIII), inter- cysteine loop 3 (of said CCK) (loop 3; between CIIIand CIV), inter-cysteine loop 4 (of said CCK) (loop 4; between CIVand CV), inter-cysteine loop 5 (of said CCK) (loop 5; between CVand CVI) and inter-cysteine loop 6 (of said CCK) (loop 6; between CVIand CI). ”CCK” or “CCK motive”, respectively, refers to a head-to-tail cyclic peptide backbone, which amino acid chain includes six conserved cysteine residue (CI-CVI) forming three intertwined disulfide bridges (CI with CIV; CII with CV; CIII with CVI), and which comprises a loop 1, a loop 2, a loop 3, a loop 4, a loop 5 and a loop 6. “Grafted cyclotides” are described in, for example, US-A12010 / 0298528; Craik loc. cit.; D’Souza loc. cit.; Wang loc. cit.; Ji loc. cit.; Lesniak loc. cit.; Gao loc. cit.; Getz loc. cit.; Gunasekera, J Med Chem 51, 2008, 7697-704; Muratspahić, 2020, loc. cit.; Mehta, J Pept Sci 26(4-5), 2020). A “grafted cyclotide” comprises a CK derived from the basis cyclotide and the (heterologous) amino acid sequence of the respective graft, grafted into said CK, thereby forming the CCK derived from the respective basis cyclotide (and including the graft). The graft is inserted into, or replaces (at least in part), one of the inter-cysteine loops of the basis cyclotide (loop 1, loop 2, loop 3, loop 4, loop 5 or loop 6). Within the grafted cyclotide, the CK part and entire CCK, respectively, is folded, i.e., all three interwined disulfide-bridges are formed. Further, the peptide backbone (including the peptide backbone of the CK part and of the graft part) is cyclized / cyclic. The graft constitutes the (biologically) active part of the grafted cyclotide (or at least the main part thereof which contributes to the overall biological activity of the grafted cyclotide). The graft is typically a biologically active amino acid sequence, like a biologically active epitope (whereas “epitope” is not limited to an epitope which can be bound by an antibody, but also covers amino acid sequence stretches which bind to a target and result in biological activity upon binding to the target (e.g., a ligand binding to a GPCR; see, e.g., Muratspahic, 2020, loc. cit.). In the context of the present invention, a CCK derived from a cyclotide (kB1) means that a CK derived from the respective cyclotide with the (heterologous) graft (dynA sequence) grafted into said CK be comprised in said CCK. “Grafting scaffold” in accordance with the present invention comprises the linear / acyclic amino acid sequence of (or derived from) the peptide backbone of the basis cyclotide (kB1), without the amino acid sequence of a graft, however, with a fully folded CK (as derived from the respective basis cyclotide). “Fully folded” (or just “folded”) in accordance with the invention means that all three interwined disulfide-bridges are formed. The “grafting scaffold” is acyclic, which means that it comprises the free (non-head-to-tail-cyclized) N- and C- termini of the comprised linear / acyclic amino acid sequence / peptide backbone. This gap in the formerly cyclic peptide backbone of (or derived from) the basis cyclotide can in principle be in any of loop 1-6. In the context of the invention, this gap is in loop 3, loop 5 or loop 6. ”CK” or “CK motive”, respectively, refers to an acyclic peptide backbone (non-head-to-tail cyclized), which amino acid chain includes six conserved cysteine residue (CI-CVI) forming three intertwined disulfide bridges (CIwith CIV; CIIwith CV; CIIIwith CVI), and which comprises five of a loop 1, a loop 2, a loop 3, a loop 4, a loop 5 and a loop 6, wherein said peptide backbone corresponds to / is derived from the peptide backbone of the cyclotide (kB1) which is linearized within one of loop 1, a loop 2, a loop 3, a loop 4, a loop 5 and a loop 6 (e.g. within loop 3, loop 5 or loop 6 in accordance with the invention). “Peptide backbone” in accordance with the present invention (sometimes termed herein also “scaffold peptide”; or just “scaffold”; cf. Fig.1) refers to the amino acid sequence as comprised in the grafted cyclotide (the respective head-to-tail-cyclized form thereof), but also to the respective linear / acyclic form. In other words, the meaning of “peptide backbone” encompasses the amino acid sequence as comprised in the grafted cyclotide in both forms, the head-to-tail-cyclized form and the linear / acyclic form. The meaning of “peptide backbone” encompasses both, the amino acid sequence (cyclic or linear) as comprised in the grafted cyclotide and the linear / acyclic amino acid sequence of the grafting scaffold and CK, respectively (without the amino acid sequence of the graft). “Peptide backbone” refers to the amino acid sequence in unfolded form. Upon folding, the linear / linearized peptide backbone of (or derived from) the basis cyclotide results in the grafting scaffold. Also the amino acid sequence of the graft as such may be termed “peptide backbone” of the graft. Kalata B1 (kB1) is the prototypical cyclotide of the Rubiaceae species Oldenlandia affinis. kB1 is well known and characterized in the art; see, for example, Gruber (Planta Med 77, 2011, 207- 20), WO-A12013 / 093045, and US-A12010 / 0298528. The particular amino acid sequence of kB1 is given herein below and is also depicted in SEQ ID NO: 1. kB1 constitutes the basis cyclotide of the grafted cyclotide of the invention; and also of a respective grafting scaffold, CCK, CK and peptide backbone. This means that the grafted cyclotide, and also the respective grafting scaffold, CCK, CK and peptide backbone, is derived from kB1. “Derived from kB1” and “kB1-derived”, respectively, in the context of the invention means that the amino acid sequence of the respective peptide backbone (of the cyclotide part) is identical or highly similar to the (corresponding) amino acid sequence of the peptide backbone of the native kB1. “Highly similar” in this respect means that some variation (e.g. mutations) of the amino acid sequence of the native kB1 backbone peptide may be allowed, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 single amino acid substitutions, or amino acid deletions, may be allowed (the lower amounts of substitutions / deletions are preferred). Preferably, (an) amino acid substitution(s) is / are (an) conservative amino acid substitution(s). The meaning of conservative amino acid substitution is well known in the art (see herein elsewhere for further details). In any case, and even even if “derived from” kB1 and mutated / variated to some extent, the grafted cyclotide, CCK, grafting scaffold, CK and peptide backbone comprises the six C- residues of the CCK of the basis kB1 and respective inter-C loops (except loop 3, 5 or 6 in the case of the grafting scaffold, CK and respective linear peptide backbones of the invention). In any case, the allowed sequence variation of the kB1-derived peptide backbone etc. is envisaged to be so that the desired biological activity of the basis cyclotide (kB1), and of the final respective grafted cyclotide, is maintained (or even improved). For example, in the context of the herein exemplified grafted cyclotides, the desired KOR-activating and -agonizing activity, and / or KOR-binding affinity, is to be maintained (at least within some range(s); see herein below for details), or even enhanced. Examples of amino acid substitutions that may be present in the grafted cyclotide, CCK, CK, grafting scaffold and respective peptide backbones are the Glu3Gln (E3Q), Glu3Ala (E3A), Glu3Asn (E3N) and / or Thr16Lys (T16K) mutation(s) (relative to the amino acid positions / residues in SEQ ID NO: 1; the T16K mutation in kB1 is also known in the art as the T20K mutation (cf., for example, Jackson, Transgenic res.32(1-2), 2023, 121-33; this mutation is thus also termed T20K herein elsewhere)). Particular examples of grafted cyclotides, CCKs, CKs, grafting scaffolds and peptide backbones of the invention are thus those which are derived from a mutant form of kB1 (for example from an E3Q kB1 mutant ([E3Q]kB1; SEQ ID NO: 2; most preferred) and / or from a T20K kB1 mutant ([T20K]kB1; SEQ ID NO: 45) and / or from an E3A kB1 mutant ([E3A]kB1; less preferred) and / or from an E3N kB1 mutant ([E3N]kB1; less preferred). This means hat the respective mutation is also present in the derived grafted cyclotides, CCKs, CKs, grafting scaffolds and peptide backbones. Without being bound by theory, the substitution of the native E residue may prevent undesired cyclization (e.g. between E and R). Instead of Q as the preferred substitute amino acid, other substitute amino acids may be used which would likewise prevent the undesired cyclization. The inter-cysteine loop 1 of the CCK and CK described herein (loop 1) and of the grafted cyclotide, grafting scaffold and peptide backbone, respectively, may comprise a Gln residue (Q), for example at amino acid position 2 of loop 1 (corresponding to amino acid position 3 in SEQ ID NO: 1 and SEQ ID NO: 2). Loop 1 may comprise a mutation which corresponds to the substitution mutation Glu3Gln (E3Q) in SEQ ID NO: 2 (relative to SEQ ID NO:1). Loop 1, loop 2 and / or loop 4 of the CCK and CK as described herein, and of the grafted cyclotide, grafting scaffold and peptide backbone, respectively, may be native loop 1 (optionally except the E3Q (or EQA) mutation; as defined above), native loop 2 and / or native loop 4, respectively, of kB1. “Native” in the context of the invention means unmutated; i.e., as depicted in SEQ ID NO:1. Loop 4 of the CCK and CK as described herein and of the grafted cyclotide, grafting scaffold and peptide backbone, respectively, may comprise or consist of a Thr residue (T) (cf. SEQ ID NO: 1; optionally except the T16K / T20K mutation; as defined above). Loop 6 of the CCK as described herein and of the grafted cyclotide, and the part thereof of the grafting scaffold and CK, and respective peptide backbone, respectively, may comprise at least the first and / or the last amino acid residue(s) of native loop 6 of kB1 (cf. SEQ ID NO: 1). In the grafted cyclotide according to the invention the dynA sequence as comprised in loop 6 may be flanked by at least the first and / or the last amino acid residue(s) of native loop 6 of kB1 (cf. SEQ ID NO:1). Respective grafting scaffolds and peptide backbones are also provided herein. In the grafted cyclotide according to the invention, the first and / or last amino acid residue(s) of (native kB1) loop 6 may be a Thr residue (T) and / or a Val residue (V), respectively. Respective grafting scaffolds and peptide backbones are also provided herein. Loop 3 of the CCK as described herein and of the grafted cyclotide, and the part thereof of the grafting scaffold and peptide backbones, may comprise at least the first and / or the last amino acid residue(s) of native loop 3 of kB1 (cf. SEQ ID NO:1). In the grafted cyclotide according to the invention, the dynA sequence as comprised in loop 3 may be flanked by at least the first and / or the last amino acid residue(s) of native loop 3 of kB1 (cf. SEQ ID NO:1). Respective grafting scaffolds and peptide backbones are also provided herein. In the grafted cyclotide according to the invention, the first and / or last amino acid residue(s) of (native kB1) loop 3 may be an Asn residue (N) and / or a Gly residue (G), respectively. Respective grafting scaffolds and peptide backbones are also provided herein. Loop 5 of the CCK as described herein and of the grafted cyclotide, and the part thereof of the grafting scaffold and CK, and respective peptide backbones, may comprise at least the first and / or the last amino acid residue(s) of native loop 5 of kB1 (cf. SEQ ID NO:1). In the grafted cyclotide according to the invention, the dynA sequence as comprised in loop 5 may be flanked by at least the first and / or the last amino acid residue(s) of native loop 5 of kB1 (cf. SEQ ID NO:1). Respective grafting scaffolds and peptide backbones are also provided herein. In the grafted cyclotide according to the invention, the first and / or last amino acid residue(s) of (native kB1) loop 5 may be a Ser residue (S) and / or a Val residue (V), respectively. Respective grafting scaffolds and peptide backbones are also provided herein. In one embodiment, the grafted cyclotide comprises the dynA sequence so that loop 3, loop 5 or loop 6, respectively, is replaced (fully or, preferably, in part); by said dynA sequence, preferably except the first and( / or) the last amino acid residue(s) of native loop 3, loop 5 or loop 6, respectively, of kB1 (cf., for example, the above-defined flanking amino acid residues). Respective grafting scaffolds and peptide backbones are also provided herein. In one embodiment, the grafted cyclotide according to the invention is not a particular grafted cyclotide selected from the group consisting of: (i) cyclo-CGETCVGGTCNTPGCKCYGGFLRRIVCTRNGLPV (T20K-DYN 1; SEQ ID NO: 42); (ii) cyclo-CGETCVGGTCNTPGCKCSWPVCYGGFLRRIRPKLK (T20K-DYN 2; SEQ ID NO: 43); and (iii) cyclo-CGETCVGGTCYGGFLRRIRPKLKCKCSWPVCTRNGLPV (T20K-DYN 3; SEQ ID NO: 44). In one embodiment, the grafted cyclotide according to the invention is not the particular grafted cyclotide cyclo-YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT ((iv); ∆L6[E3Q]kB1-dynA; SEQ ID NO: 5). In one embodiment, the grafted cyclotide of the invention does not comprise a particular amino acid sequence selected from the group consisting of the amino acid sequences as depicted in (i), (ii), (iii) and (iv), above. This embodiment also encompasses the optional exclusion of the respective grafting scaffolds and peptide backbones. This embodiment encompasses the respective grafted cyclotides, grafting scaffolds and peptide backbones which do not comprise the respective particular cyclotide part of an amino acid sequence as depicted in (i), (ii), (iii) or (iv), above. In principle, any graft may be grafted into the grafting scaffold of the invention; and the invention also relates the resulting respective grafted cyclotides and respective peptide backbones. However, the most preferred grafts in accordance with the invention are dynA- derived amino acid sequences (the dynA sequence disclosed herein). An amino acid sequence derived from “dynorphin A” and a “dyn A-derived” amino acid sequence, respectively, means high amino acid sequence similarity to native dynA (as depicted in SEQ ID NO: 36). This allows some sequence variation, provided that the respective dynA- derived sequence exhibits the (desired) biological activity / function of the native dynorphin A (at least within some ranges; see below for respective examples), or even exhibits an improved biological function (as compared to native dynA); in particular when constituting the graft of the grafted cyclotides as disclosed herein. The respective biological activity / function is, for example, the KOR-activating / -agonizing activity and / or the KOR-binding affinity (see, for example, herein elsewhere for further details). Means and methods for conveniently testing the biological activity (function of a given variant of dynA (dynA-derived variant) are known in the art and are disclosed herein and in the appended examples. In accordance with the invention, the dynA sequence may consist of (or may comprise) at least (the first) 8 (preferred), 9 (preferred), 10, 11 (preferred), 12 or 13 (preferred) amino acid residues of the amino acid sequence YGGFLRRIRPKLK (SEQ ID NO: 36 dynA). These amino acid residues may be consecutive or non-consecutive (but in the same order as in SEQ ID NO:36). Further, the dynA sequence may consist of (or comprise) at least (the first) 8, 9, 10, 11, 12 or 13 amino acid residues of the amino acid sequence YGGFLRRIRPKLK (consecutive; or non- consecutive, but in the same order as in SEQ ID NO:36), but having 1, 2, 3, 4, 5, 6, 7, or 8 (conservative) amino acid substitution(s), for example having 1, 2, 3 or 4 of Arg7, Ile8, Pro10 and Lys11 (conservatively) substituted. In principle, lower variation and lower values of substituted amino acid residues, respectively, are preferred. The technical meaning of conservative amino acid substitution is well known in the art. For example, an amino acid substitution is conservative (in the context of the invention), when the replacement amino acid(s) belong(s) to the same category of amino acids than the amino acid(s) to be replaced. For example, an acidic amino acid may be replaced by another acidic amino acid, a basic amino acid may be replaced by another basic amino acid, an aliphatic amino acid may be replaced by another aliphatic amino acid, and / or a polar amino acid may be replaced by another polar amino acid. The meaning of the terms ”acidic amino acid(s)”, “basic amino acid(s)”, “aliphatic amino acid(s)” and “polar amino acid(s)” are known in the art (see, for example, Stryer, Biochemie, Spectrum Akad. Verlag, 1991, Item I. 2.). These terms are correspondingly used throughout the invention. In particular, the term ”acidic amino acid(s)” as used herein is intended to mean an amino acid selected from the group comprising Asp, Asn, Glu, and Gln, the term “basic amino acid(s)” as used herein is intended to mean an amino acid selected from the group comprising Arg, Lys and His, the term “aliphatic amino acid(s)” as used herein is intended to mean any amino acid selected from the group comprising Gly, Ala, Ser, Thr, Val, Leu, Ile, Asp, Asn, Glu, Gln, Arg, Lys, Cys and Met, and the term “polar amino acid(s)”as used herein is intended to mean any amino acid selected from the group comprising Cys, Met, Ser, Tyr, Gln, Asn and Trp. Further, a conservative amino acid substitution in accordance with the invention may mean that F is replaced by I, L or Y; G is replaced by A, C, D, E or R; I is replaced by F, L, M, N or V; K is replaced by E, M, N, Q, R or T; L is replaced by F, H, I, M, P, Q, R, V or W; P is replaced by H, L, Q, R or S; R is replaced by C, G, H, K, L, M, P, Q, T or W; Y is replaced by C, D, F, H, N or S. Particular (conservative) amino acid substitutions which may occur in accordance with the invention are the substitution of Y by Nα-AcTyr, DTyr, Phe or Phe(p-Br) and / or the substitution of G by DAla. In principle, any amino acid configuration may be present in the context of the peptide backbone of the grafted cyclotides and respective grafting scaffolds, grafts, peptide backbones) of the invention. In general, most naturally occurring amino acids are in the L-configuration. Thus, also in the context of the invention, there is a general preference for amino acids in the L-configuration. In the context of the invention, however, one or more of the amino acid residues of the provided grafted cyclotides (and respective grafting scaffolds, grafts, peptide backbones) may also be in the D-configuration. The respective peptide backbones in the grafted cyclotides etc. may thus have a certain pattern of D- and L-amino acid residues. Also in this context, however, the resulting grafted cyclotide must be a grafted cyclotide in accordance with the invention and function accordingly (for example as described herein elsewhere. The skilled person is readily in the position to test which amino acid residue(s) of a grafted cyclotide etc. should be in the L-configuration and which may be in the D-configuration, i.e. to figure out a suitable pattern of D-and L-amino acid residues (i.e. a pattern which results in a functional grafted cyclotide etc. in accordance with the invention). In this context, the skilled person may, for example, rely on the tests / assays disclosed herein and in the appended examples (e.g. one or more of the (pharmacological) tests / assays for testing as described herein elsewhere and in appended examples, infra). In general, the meaning of the term “amino acid” or “amino acid residue” is known in the art and is used herein accordingly. When an “amino acid” is a component of a peptide / protein, the term “amino acid” is used herein in the same sense than “amino acid residue”. An “amino acid” or “amino acid residue” as referred to herein may be a naturally-occurring amino acid (preferred), more preferably a naturally-occurring L-amino acid. However, as mentioned, an “amino acid” or “amino acid residue” in context of this invention may also be a D-amino acid, or an un-typical or non-naturally-occurring (i.e. a synthetic) amino acid, like, for example, methylated amino acid norleucine, ß-alanine, Dap or selenocysteine. It will also be acknowledged by the one skilled in the art that one or several of the amino acids as comprised in the respective peptide backbones may be modified. In accordance therewith, any amino acid as used / defined herein may, in principle, also represent its modified form. For example, a Cys residue as used herein may be a modified Cys residue like a homocysteine residue (provided that the 3 interwined disulphide bridges can be formed). Modifications may, among others, be a methylation or acylation, or the like. In principle, however, non-modified amino acid residues are preferred. In any case, it is envisaged that a grafted cyclotide described herein which comprises such (a) modification(s) or modified amino acid(s) is still functionally active in accordance with the invention (cf. herein elsewhere). Respective assays for determining whether a given grafted cyclotide fulfils this requirement, are known to the one skilled in the art and are, among others, also described herein, e.g. in the example part and / or herein elsewhere. For example, the dynA sequence to be used as a graft in accordance with the invention may comprise one or more of the following mutations: L-Arg7 replaced by D-Arg7 or replaced by N(alpha)-metyl-Arg7 (Nα-metyl-Arg7); L-Lys11 replaced by D-Lys or replaced by N(alpha)-metyl-Lys11 (Nα-metyl-Lys11); L-Ile8 replaced by D-Ile or replaced by 2,3 diaminopropionic acid (Dap); and / or L-Pro10 replaced by D-Pro or replaced by Dap; All the above mutations are given in relation to SEQ ID NO:36. One particular modification that might be present in the dynA sequence of the invention (alone or in addition to one or more of the other mutations / modifications described herein) is a modification of L-Arg7 (e.g. one of the two described above). Arg7 may even be deleted. An example of a resulting dynA sequence in accordance with the invention may be YGGFLRIRPK (SEQ ID NO: 52). Particular examples of dynA sequences which may be comprised as the graft in the grafted cyclotide (and in the respective peptide backbone) of the invention are dynA sequences which consist of (or comprise) an amino acid sequence selected from the group consisting of: (i) YGGFLRRIRPKLK (SEQ ID NO: 36; more preferred). (ii) YGGFLRRI (SEQ ID NO: 37; preferred); (iii) YGGFLRRIR (SEQ ID NO: 38; preferred); (iv) YGGFLRRIRP (SEQ ID NO: 39); (v) YGGFLRRIRPK (SEQ ID NO: 40; preferred); and (vi) YGGFLRRIRPKL (SEQ ID NO: 41). Particular examples of respective mutant forms of the above-depicted amino acid sequences, which may also be comprised as the graft in the grafted cyclotide (and in the respective peptide backbone) of the invention are depicted in SEQ ID Nos: 46 (more preferred), 47 (preferred), 48 (preferred), 49, 50 (preferred), and 51. The dynA sequence may, optionally in addition to (one or more of) the other described mutation(s), have Tyr1 and / or Gly2 (conservatively) substituted (e.g. by Nα-AcTyr1, D-Tyr1, Phe1 or Phe(p-Br)1 and / or D-Ala2, respectively). The most preferred dynA sequence sequence in accordance with the invention is native dynA (1-13) as depicted in SEQ ID NO: 36; or a mutant form thereof as described above or as depicted in SEQ ID NO: 51. Particular examples of (kB1-derived) peptide backbones (without the dynA sequence) which may be comprised in the grafted cyclotide or grafting scaffold of the invention are peptide backbones which consist of (or comprise) an amino acid sequence selected from the group consisting of: (i) GCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 33; kB1-derived backbone of, for example, ^L3[E3Q]kB1-dynA or ∆L3[E3Q]kB1-dynA3.4); (ii) VCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 34; kB1-derived backbone of, for example, ^L5[E3Q]kB1-dynA or ∆L5[E3Q]kB1-dynA2.4); and (iii) VCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 35; kB1-derived backbone of, for example, ^L6[E3Q]kB1-dynA or ∆L6[E3Q]kB1-dynA1.4). Particular examples of peptide backbones (including the dynA sequence) which may be comprised in the grafted cyclotide of the invention are peptide backbones which consist of (or comprise) an amino acid sequence selected from the group consisting of: (i) YGGFLRRIRPKLKGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 18; backbone of ^L3[E3Q]kB1-dynA; SEQ ID NO: 19; backbone of ∆L3[E3Q]kB1-dynA3.4); (ii) YGGFLRRIRPKLKVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 20; backbone of ^L5[E3Q]kB1-dynA; SEQ ID NO: 21; backbone of ∆L5[E3Q]kB1-dynA2.4); (iii) YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 22; backbone of ^L6[E3Q]kB1-dynA; SEQ ID NO: 23; backbone of ∆L6[E3Q]kB1-dynA1.4); (iv) YGGFLRRIRPKGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 24; backbone of ^L3[E3Q]kB1-dynA3.1); (v) YGGFLRRIRGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 25; backbone of ^L3[E3Q]kB1-dynA3.2); (vi) YGGFLRRIGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 26; backbone of ^L3[E3Q]kB1-dynA3.3); (vii) YGGFLRRIRPKVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 27; backbone of ^L5[E3Q]kB1-dynA2.1); (viii) YGGFLRRIRVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 28; backbone of ^L5[E3Q]kB1-dynA2.2); (ix) YGGFLRRIVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 29; backbone of ^L5[E3Q]kB1-dynA2.3); (x) YGGFLRRIRPKVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 30; backbone of ^L6[E3Q]kB1-dynA1.1); (xi) YGGFLRRIRVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 31; backbone of ^L6[E3Q]kB1- dynA1.2); and (xii) YGGFLRRIVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 32; backbone of ^L6[E3Q]kB1- dynA1.3). Particular examples of grafted cyclotides according to the invention are selected from the group consisting of: (i) cyclo-YGGFLRRIRPKLKGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA; SEQ ID NO: 3; SEQ ID NO: 9; ∆L3[E3Q]kB1-dynA3.4); (ii) cyclo-YGGFLRRIRPKLKVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA; SEQ ID NO: 4; SEQ ID NO: 13; ∆L5[E3Q]kB1-dynA2.4); (iii) cyclo-YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA; SEQ ID NO: 5; SEQ ID NO: 17; ∆L6[E3Q]kB1-dynA1.4); (iv) cyclo-YGGFLRRIRPKGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.1; SEQ ID NO: 6); (v) cyclo-YGGFLRRIRGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.2; SEQ ID NO: 7); (vi) cyclo-YGGFLRRIGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.3; SEQ ID NO: 8; (vii) cyclo-YGGFLRRIRPKVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.1; SEQ ID NO: 10); (viii) cyclo-YGGFLRRIRVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.2; SEQ ID NO: 11); (ix) cyclo-YGGFLRRIVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.3; SEQ ID NO: 12); (x) cyclo-YGGFLRRIRPKVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.1; SEQ ID NO: 14); (xi) cyclo-YGGFLRRIRVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.2; SEQ ID NO: 15); and (xii) cyclo-YGGFLRRIVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.3; SEQ ID NO: 16). The present invention also relates to the respective (cyclic) peptide backbones. Particular examples of respective mutated forms of the above-depicted grafted cyclotides have at least one of the mutations as described above or herein elsewhere with respect to the cyclotide part (CK, grafting scaffold, respective peptide backbone); e.g., 1, 2, 3 (or more) of these mutations (e.g., in addition to the E3Q mutation). These and other / further examples of mutant forms of the above depicted grafted cyclotides may have at least one of the mutations as described above with respect to the graft part (dynA sequence); e.g., 1, 2, 3, 4 (or more) of these mutations. Particular examples of such mutations in the graft part are the substitution mutations to Me-Arg7, D-Arg7, D-Ile8, Dap8, D-Pro10, Dap10, Me-Lys11 and / or D-Lys11 (see above). Generally, the grafted cyclotide according to the invention is envisaged to exhibit (or is capable of exhibiting) at least one, more (e.g. at least two or three), or (preferably) all of the desired and advantageous (biological) functions as described herein, in particular the (biological) functions of ΔL3[E3Q]kB1-dynA, ΔL5[E3Q]kB1-dynA or ΔL6[E3Q]kB1-dynA, respectively. Most relevantly, the grafted cyclotide according to the invention is envisaged to be a (specific) KOR agonist (full or, preferably, partial), e.g., a (specific) a G-protein-biased KOR agonist. In particular, the grafted cyclotide according to the invention is envisaged to bind to KOR (or to be capable of binding to KOR), and( / or) to be a KOR agonist. For example, the grafted cyclotide according to the invention binds to KOR with at a nM affinity; i.e. high affinity (see below), may have a preference for modulating G-protein over β-arrestin signaling pathways (G-protein- biased agonizing activity; no / low recruitment of β-arrestin, e.g. β-arrestin-1 and / or β-arrestin- 2), and / or may bind to KOR with an enhanced selectivity for KOR over MOR and / or DOR (see also below). More particular, the grafted cyclotide according to the invention is envisaged to exhibit (or is capable of exhibiting) at least one, more (e.g. at least two, three, four or five), or (preferably) all of the following (or herein elsewhere described) biological functions: The grafted cyclotide (fully or, preferably, partially) activates the KOR; i.e. said grafted cyclotide is a (full or, preferably, partial) KOR agonist (e.g. with an ECmax in the range of 80-170%, preferably in the range of 100-150% (as compared to Dynorphin A 1-13 (100%)), and / or with a potency / efficacy (cAMP; EC50) in the range of 10 nM to 130nM, preferably in the range of 20 nM to 120 nM). Activation and potency / efficacy (cAMP; EC50) may be determined by a functional cAMP inhibition assay (e.g. as disclosed in the appended examples and in Muratspahic, J. Med. Chem. 64, 2021, 9042-55). ECmax may be about 109% and / or potency / efficacy (cAMP; EC50) may be about 28 nM for ΔL3- grafted cyclotides as defined herein; ECmaxmay be about 128% and / or potency / efficacy (cAMP; EC50) may be about 112 nM for ΔL5-grafted cyclotides as defined herein; ECmaxmay be about 139% and / or potency / efficacy (cAMP; EC50) may be about 69 nM M for ΔL6-grafted cyclotides as defined herein. A non-limiting reference is, for example, also made to Table 1 in this respect. The grafted cyclotide binds to KOR with a high affinity (e.g. at a nanomolar affinity); like an affinity corresponding to a Ki in the range of 0.5 nM to 50 nM or 0.5 nM to 10 nM, preferably in the range of 1.0 nM to 7 nM; e.g. to a Ki value of about 1.4 nM for ΔL3-grafted cyclotides as defined herein; to a Ki value of about 3.2 nM for ΔL5-grafted cyclotides as defined herein; to a Ki value of about 6.2 nM for ΔL6-grafted cyclotides as defined herein. Affinity may be determined by a radioligand competition binding assay (e.g. as disclosed in the appended examples and in Muratspahic, 2021, loc. cit.). A non-limiting reference is, for example, also made to Table 1 in this respect. A KOR ligand is partially agonizing, if it agonizes KOR only with a reduced potency and / or efficacy, e.g., as compared to a known KOR agonist (e.g. U50488 or dynA). A KOR ligand is partially agonizing, for example, if it agonizes KOR with (an) increased value(s) for Emaxand / or EC50as compared to a known KOR agonist (e.g. U50,488 or dynA); e.g. in a cAMP inhibition assay (see herein elsewhere). For example, a KOR ligand is partially agonizing, if it agonizes KOR with an Emaxof <80 %, 20-80 %, 40-80 % or 50-80 % as compared to, for example, dynA. The grafted cyclotide may exhibit a certain G protein activation efficacy (via KOR), e.g. enhanced, simlilar or reduced as compared to dynA. (e.g. 60-89%, 20-59%, or 10-19% of a certain G protein activation efficacy of dynA). In principle, G protein activation efficacy may also be higher as compared to dyn A. For ΔL3-grafted cyclotides as defined herein, Gαi1 recruitment may be in the range of 60-89% of the Gαi1recruitment of dynA (e.g. (about) 85%); Gαi2recruitment may be in the range of ≥90% of the Gαi2 recruitment of dynA (e.g. (about) 106%); Gαi3 recruitment may be in the range of ≥90% of the Gαi3 recruitment of dynA (e.g. (about) 101%); Gαo1 recruitment may be in the range of ≥90% of the Gαo1 recruitment of dynA (e.g. (about) 99%); Gαq recruitment may be in the range of ≥90% of the Gαq recruitment of dynA (e.g. (about) 120%); Gα13 recruitment may be in the range of 20-59% of the Gα13 recruitment of dynA (e.g. (about) 47%); and / or Gα15 recruitment may be in the range of ≥90% of the Gα15 recruitment of dynA; e.g. (about) 132%. For ΔL5-grafted cyclotides as defined herein, Gαi1 recruitment may be in the range of 20-59% of the Gαi1 recruitment of dynA (e.g. (about) 57%); Gαi2 recruitment may be in the range of 60-89%of the Gαi2 recruitment of dynA (e.g. (about) 79%); Gαi3recruitment may be in the range of 20-59% of the Gαi3recruitment of dynA (e.g. (about) 59%); Gαo1recruitment may be in the range of 60-89% of the Gαo1recruitment of dynA (e.g. (about) 69%); Gαq recruitment may be in the range of 60-89% of the Gαq recruitment of dynA (e.g. (about) 75%); Gα13recruitment may be in the range of 60-89% of the Gα13recruitment of dynA (e.g. (about) 76%); and / or Gα15recruitment may be in the range of 60- 89%of the Gα15recruitment of dynA; e.g. (about) 75%. For ΔL6-grafted cyclotides as defined herein, Gαi1 recruitment may be in the range of 60-89% of the Gαi1 recruitment of dynA (e.g. (about) 81%); Gαi2 recruitment may be in the range of ≥90% of the Gαi2 recruitment of dynA (e.g. (about) 108%); Gαi3 recruitment may be in the range of ≥90% of the Gαi3 recruitment of dynA (e.g. (about) 98%); Gαo1 recruitment may be in the range of ≥90% of the Gαo1 recruitment of dynA (e.g. (about) 98%); Gαq recruitment may be in the range of ≥90% of the Gαq recruitment of dynA (e.g. (about) 111%); Gα13 recruitment may be in the range of ≥90% of the Gα13 recruitment of dynA (e.g. (about) 113%); and / or Gα15 recruitment may be in the range of ≥90% of the Gα15 recruitment of dynA; e.g. (about) 113%. G protein activation efficacy (via KOR) can be measured as, for example, described in Muratspahić (nature communications 14, 2023, 1-17). A non limiting reference is, for example, also made to Table 5 and Example 12 in this respect. The grafted cyclotide induces (via KOR) β-arrestin recruitment, e.g. β-arrestin-1 and / or β- arrestin-2 recruitment, in a similar manner as dyn A; or, preferably, with a reduced efficacy as compared to dynA (e.g. 60-89%, 20-59%, 10-19%, or 1-9%, or even ≤0%, of the β-arrestin-2 and / or -1 recruitment of dynA). In principle, β-arrestin recruitment, e.g. β-arrestin-1 and / or β- arrestin-2 recruitment, may also be higher as compared to dyn A (less preferred). For ΔL5- grafted cyclotides as defined herein, β-arrestin-1 recruitment may be in the range of 20-59% of the β-arrestin-1 recruitment of dynA (e.g. (about) 25%); and / or β-arrestin-2 recruitment may be in the range of ≤0% of the β-arrestin-2 recruitment of dynA; e.g. (about) -34%. For ΔL3- grafted cyclotides as defined herein, β-arrestin-1 recruitment may be in the range of ≥90% of the β-arrestin-1 recruitment of dynA (e.g. (about) 124%); and / or β-arrestin-2 recruitment may be in the range of ≥90% of the β-arrestin-2 recruitment of dynA; e.g. (about) 110%. For ΔL6- grafted cyclotides as defined herein, β-arrestin-1 recruitment may be in the range of ≥90% of the β-arrestin-1 recruitment of dynA (e.g. (about) 143%); and / or β-arrestin-2 recruitment may be in the range of ≥90% of the β-arrestin-2 recruitment of dynA; e.g. (about) 102%. β-arrestin recruitment can be measured as, for example, described in Dürrauer (Sci Rep 9, 2019, 19295) or WO2021 / 186035. A non-limiting reference is, for example, also made to Table 6 and Example 11 in this respect. The grafted cyclotides of the invention (in particular the (preferred) mutated forms thereof; see above / herein elsewhere; cf. the appended examples) may be particularly stable; and / or may have a high / improved retention and / or half life time (for example in a patient´s body (e.g. in blood or serum)). As such, grafted cyclotides are preferred to lack sites susceptible for hydrolysis or cleaving proteases, like, for example, serum proteases. The meanings of the terms “hydrolysis” and “(serum) proteases” and the structure of the respective sites are well known in the art. For example, the grafted cyclotides may be stable in (human) serum for ≥0.5 h (e.g. ≥50% (preferably ≥75%) of the grafted cyclotides remains in the (human) serum after (about) 0.5 h; ≥25% (preferably 50≥%) of the grafted cyclotides remains in the (human) serum after (about) 1.0 h; ≥20% (preferably ≥30%) of the grafted cyclotides remains in the (human) serum after (about) 1.5 h; and / or ≥15% (preferably ≥25%) of the grafted cyclotides remains in the (human) serum after (about) 2.0 h). The skilled person is readily able to test whether a grafted cyclotide, exhibits any of the herein described (biological) functions; like the herein described (biological) functions of the grafted cyclotide as depicted in SEQ ID NOs: 3, 4 or 5. These functions include those which are described herein elsewhere. SEQ ID NOs: 3, 4 or 5 may be used as controls in this respect. Guidance and assays for testing the (biological) functions are known in the art (see, for example, the respective scientific papers and / or patent literature cited herein) and are provided herein and in the appended examples (see, for example, Example 1 and Example 10). For example, whether a grafted cyclotide is an agonist of the KOR / agonizes the KOR can be tested as described in Muratspahić (J Med Chem 64, loc. cit.) or Duerrauer (Sci Rep 9, 2019, 19295), and as in appended Examples 6 and 8. For example, a cAMP assay (e.g. according to the Cisbio protocol) and / or Schild regression analysis may be applied in this respect. For example, whether a grafted cyclotide specifically binds to KOR (but not to MOR and DOR can be tested as described in Muratspahić (J Med Chem 64, loc. cit.). For example, whether a grafted cyclotide binds to grafted cyclotide KOR can be tested as described in Chavkin (loc. cit.) and Naqvi (loc. cit.), and in appended Example 7. For example, whether a grafted cyclotide is stable in (human) serum can be tested as described in Muratspahić (J Med Chem 64, loc. cit.). The KOR, in particular, the human KOR (hKOR), is well known in the art and is, for example, described in Lalanne (Front Psychiatry 5, 2014, 170) and Du (Nat. Commun.7, 2016, 11120). In principle, when reference to KOR is made herein, any KOR is meant, in particular a KOR of any (animal) species. A KOR referenced herein may, for example, be a KOR of human, mouse, rat, rabbit, monkey or goat etc. origin (see, for example, UniProt entries: OPRK_MOUSE P33534, OPRK_RAT P34975). Preferably, the KOR is hKOR (see, for example, UniProt entry: OPRK_HUMAN P41145). A detailed characterization of the hKOR, including the particular amino acid sequence information, is derivable from the database entry https: / / www.uniprot.org / uniprot / P41145. In general, it is preferred that the KOR to be targeted by the grafted cyclotide of the invention is the KOR of a patient to be treated. For example, if the patient to be treated is a human, the KOR to be targeted is preferably hKOR. Assays for testing the relevant biological function(s) of the KOR are disclosed herein and known in the art. Respective assays are, for example, described in the appended examples (e.g. Examples 6, 7 and 8). Further, multiple agonists of the KOR are known in the art (see, e.g. https: / / www.guidetopharmacology.org / GRAC / ObjectDisplayForward?objectId=318&familyId= 50&familyType=GPCR). Non limiting examples of known KOR agonists are U50,488, dynA (e.g. dynA1-17 or dynA1-13), nalfurafine etc.; see also https: / / www.guidetopharmacology.org / GRAC / ObjectDisplayForward?objectId=318&familyId=50&familyType=GPCR). Agonists of the KOR as known in the art may, for example, be used as reference compounds / controls when testing / assaying whether a grafted cyclotide functions in accordance with the invention, i.e. exhibits the relevant / advantageous property(ies) / (biological)function(s) of the grafted cyclotide of the invention (e.g. acting as a (superior) KOR agonist. For example, a KOR agonist known in the art may be used a control research tool / pharmacological probe when testing whether a given grafted cyclotide (as, for example, structurally defined herein) acts like SEQ ID NO: 3, 4 or 5 or just like (or in relation to) the known KOR agonist (e.g. U50,488); or, if SEQ ID NO: 3, 4 or 5 is used as a further control research tool / pharmacological probe, like this amino acid itself. As mentioned, the grafted cyclotide of the invention is envisaged to act as a (h)KOR agonist / agonist of (h)KOR. The meaning of “(h)KOR agonist” and “agonist of the (h)KOR” is known in the art and the respective terms are used herein accordingly (see above and, e.g., https: / / www.guidetopharmacology.org / GRAC / ObjectDisplayForward?objectId=318 &familyId=50&familyType=GPCR). In the context of the invention, being an “agonist” of the KOR and exhibiting “agonistic” function on the KOR, respectively, means that the KOR activity, i.e. the relevant biological function(s) of the KOR, is(are) increased or induced. More particular, being an “agonist” of the KOR and exhibiting “agonistic” function on the KOR, respectively, means in the context of the invention that a KOR-mediated opioid stimulus, e.g. intracellular cAMP reduction, is increased or induced. This, for example, leads to an activation (increase or induction) of the RAF / MEK1 / 2 / ERK1 / 2 and / or the JAK2 / STAT3 signalling cascades (Borniger, J. Neurosci 36(47), 2016, 11831-3). As mentioned, a preferred “agonist” of the KOR modulates the G protein over the β-arrestin signaling pathway. For example, a KOR ligand may be agonizing (activating) in accordance with the invention, if it agonizes KOR with the same potency, a similar potency or even with a lower potency (for example, if KOR in the gut is targeted) as compared to a (typical) KOR agonist (e.g. U50,488 or dynA; or SEQ ID NO: 3, 4 or 5). It is particularly envisaged that the grafted cyclotides of the invention (in particular the (preferred) mutated forms thereof; see above; cf. the appended examples) can be produced by the ‘plug and play’ approach, respectively (e.g. as described herein) and the preparing method of the invention in an efficient manner (e.g. at high yields and / or with less / low side products; cf., for example, Table 4). If not indicated differently herein elsewhere, “inhibiting”, “decreasing”, “blocking”, “suppressing” or “reducing” and the like, in the context of the present invention is envisaged to mean that the initial status (for example status of KOR affinity, agonizing potency and / or efficacy of a grafted cyclotide, activity of a grafted cyclotide, stability of a grafted cyclotide etc.; and the respective KOR function) is lowered (in vitro and / or in vivo) by, for example, at least 10%, by at least 20%, by at least 30%, by at least 50%, by at least 80%, by at least 90%, at least 95%, by at least 99% or even by 100% (in principle, the higher values of percentage are preferred). The skilled person is readily in the position to test the respective degree of “inhibiting”, “decreasing”, “blocking”, “suppressing” or “reducing”. Moreover, the skilled person is readily in the position to determine for a given drug (e.g. grafted cyclotide as defined (e.g. by a structure) or as disclosed herein) the IC50 for the respective “inhibiting”, “decreasing”, “blocking”, “suppressing” or “reducing” effect / activity. Likewise, if not indicated differently herein elsewhere, “increasing”, “inducing” or “improving”, and the like, in the context of the present invention particularly means that the initial status (for example status of KOR affinity, agonizing potency and / or efficacy of a grafted cyclotide, activity of a grafted cyclotide, stability of a grafted cyclotide etc.; and the respective KOR function) is increased (in vitro and / or in vivo) by, for example, at least 10%, by at least 20%, by at least 30%, by at least 50%, by at least 80%, by at least 90%, at least 95%, by at least 99% or by at least 100%; or by at least 2, 3, 4, 5, 6, 7, 8, 9 or 10-fold (in principle, the higher values of percentage are preferred). In particular, “increasing” means that there is already an initial degree of activity / status (baseline) which is further “increased”. In particular, “inducing” means that there is (substantially) no initial degree of activity / status which is then “induced”. The skilled person is readily in the position to test the respective degree of “increasing”, “inducing” or “improving”. Moreover, the skilled person is readily in the position to determine for a given drug (e.g. grafted cyclotide as defined (e.g. by a structure) or as disclosed herein) the IC50 for the respective “increasing”, “inducing” or “improving” effect / activity. The present invention further relates to a pharmaceutical composition comprising the grafted cyclotide according to the invention. The pharmaceutical composition may further comprise a pharmaceutically acceptable carrier. The grafted cyclotide of the invention, or the pharmaceutical composition comprising it, may be for use in the treatment, amelioration or prophylaxis of a KOR-related disease, in particular of a disease resulting from or coming along with a decreased KOR activity and / or which is treatable by KOR agonism / an increased KOR activity. In case the grafted cyclotide according to the invention is incapable of entering the BBB, or incapable of modulating KOR function in the CNS, it may particularly be useful in treating, ameliorating or preventing diseases or disorders which manifest / occur in the periphery / PNS (outside the CNS (spinal cord and brian)). Respective examples are (chronic) peripheral pain, and the like, or (peripheral) inflammation, and the like. In one aspect, the grafted cyclotide of the invention, or the pharmaceutical composition comprising it, may be for use in the treatment of pain, including acute and chronic pain, nociceptive pain, inflammatory pain, visceral pain, cancer-related pain, postoperative pain, musculoskeletal and neuropathic pain, but is not limited to these. In one aspect, the present invention also relates to a grafted cyclotide of the invention, and to a pharmaceutical composition comprising it, and optionally a pharmaceutical carrier, for use in treating, ameliorating or preventing (chronic) pain, in particular (chronic) abdominal pain, (chronic) visceral pain or (chronic) central pain, neuropathic pain (e.g. central or, preferred, peripheral (neuropathic) pain) and / or pain resulting from / coming along with MS; (chronic) peripheral pain is preferred; In one aspect, the grafted cyclotide of the invention, or the pharmaceutical composition comprising it, may also be for use in the treatment of pruritus (nalfurafine and difelikephalin have been clinically used to treat uremic pruritus) and neurological disorders such as epilepsy (preclinical data of efficacy of common KOR drugs are available in the literature). In particular, in view of the data provided herein, it is highly credible that the grafted cyclotide of the invention, and the pharmaceutical composition comprising it, would be active against such disorders. In one aspect, the grafted cyclotide of the invention, and the pharmaceutical composition comprising it, may, due their KOR agonist activity, have an anti-itching effect. The grafted cyclotide of the invention, and the pharmaceutical composition comprising it, may thus be used for the treatment of itching and disorders associated with itching. In one aspect, the grafted cyclotide of the invention may also be for use in (iii) neuroprotection, more specifically remyelination (e.g. for therapy of CNS lesions in MS or AD); (iv) treating, ameliorating or preventing MS (e.g. treatment by therapy or prophylactic / preventive treatment); (v) remyelination (i.e. its induction or increase), in particular of oligodendrocytes, and / or improving (e.g. reducing or curing / healing) CNS lesions (e.g. brain lesions); and / or (vi) preventing or reducing demyelination (in particular of oligodendrocytes) and / or preventing the formation of CNS lesions (e.g. brain lesions) and / or reducing existing CNS lesions (e.g. brain lesions). In one particular aspect, the present invention relates to a pharmaceutical composition comprising the grafted cyclotide according to the invention, and optionally a pharmaceutical carrier, for use in (i) treating (peripheral) inflammation (e.g. inflammatory bowel disease (IBD), like ulcerative colitis or Crohn's disease); and / or (ii) treating (chronic) (peripheral) pain, e.g. (chronic) abdominal pain, (chronic) visceral pain, (chronic) peripheral neuropathic pain, diarrhea, rectal bleeding, fatigue and / or weight loss, in particular (chronic) (peripheral) pain, e.g. (chronic) abdominal pain, (chronic) visceral pain, (chronic) peripheral neuropathic pain, diarrhea, rectal bleeding, fatigue and / or weight loss relating to / coming along with (i); and / or (ii) treating itching and / or disorders associated with itching. The cyclized grafted cyclotide, and pharmaceutical composition comprising it, to be medically used in accordance with the invention may provide the advantageous property of contributing to (a) less adverse effect(s), and (an) improved profile(s) of (an) adverse effect(s), respectively. In the context of one aspect of the invention, adverse effects, in particular KOR-dependent adverse effects (predominantly centrally-mediated (or (also) peripherally-mediated)), more particular adverse effects resulting from β-arrestin recruitment (e.g. β-arrestin-2 and / or β- arrestin-1 recruitment) and / or from recruitment of one G protein alpha anlog over other G- proteins, may be reduced / ameliorated or avoided in accordance with the invention. Such adverse effects are, for example, (adverse effects related to) opioid crisis / tolerance and / or dysphoria, sedation, diuresis and / or hallucinations. Thus, in the context of one aspect of the treatment methods and related diseases, defects and / or symptoms described herein, one or more of such adverse effects is / are to be reduced / ameliorated or avoided. The grafted cyclotide or the pharmaceutical composition according to the invention may be for use in a method for treatment, and / or may be administered to a patient in need of the treatment in / at a pharmaceutically active amount / dose. The present invention further relates to a method of producing a pharmaceutical composition, e.g. for the treatments / uses described herein. Said method may comprise the step of mixing (a) grafted cyclotide as defined herein (and optionally (a) further active agent(s)) with a pharmaceutically acceptable carrier, for example a pharmaceutically acceptable carrier, excipient or diluent as defined herein elsewhere. The method for producing a pharmaceutical composition may comprise the step of mixing (a) grafted cyclotide as defined herein, and a pharmaceutically acceptable carrier, for example a pharmaceutically acceptable carrier / excipient / diluent as defined herein elsewhere. The present invention further relates to a kit / kit of contents / kit of parts, said kit comprising a grafted cyclotide of the invention (and optionally, at least one further (active) agent). The present invention further relates to a grafted cyclotide or pharmaceutical composition of the invention as part of a kit / kit of contents / kit of parts, wherein the grafted cyclotide or the pharmaceutical composition may (separately and independently from said kit) be for use in accordance with the invention (e.g. in the medical uses described herein elsewhere). The present invention further relates to a kit / kit of contents / kit of parts comprising a grafted cyclotide or pharmaceutical composition of the invention, wherein said pharmaceutical composition and / or said grafted cyclotide may (separately and independently from the kit) be for use in accordance with the invention (e.g. in the uses described herein elsewhere). In the context of the kit / kit of contents / kit of parts of the invention, and the respective pharmaceutical compositions / cyclic peptide(s) / grafted cyclotide(s), but also in the context of the pharmaceutical compositions in general as described herein, the grafted cyclotide may be contained in a (single) container or vial, and / or (a) further (active) agent(s) may be contained in (a) further container(s) or vial(s). What is said herein elsewhere with respect to the medical uses, treatment methods and pharmaceutical composition also applies to the kit. In the context of the pharmaceutical composition according to the invention or of the pharmaceutical composition for use according to the grafted cyclotide or pharmaceutical composition may be administered systemically. In the context of the pharmaceutical composition according to the invention or the pharmaceutical composition for use according to the invention, the grafted cyclotide or the respective pharmaceutical composition may be administered parenterally (e.g. s.c.; i.v.; i.m.; i.a.), perorally (preferred; e.g. in form of tablets; pills; capsules; powders; solutions; suspensions), rectally (e.g. by suppository) or bronchially (e.g. by inhalation (e.g. of a spray; aerosol; via a nebulizer; via an inhaler)). In accordance with the present invention, the disclosed pharmaceutical composition or grafted cyclotide, can / will be administered in a pharmaceutically / therapeutically effective dose. This means that a pharmaceutically / therapeutically effective amount of the grafted cyclotide (active ingredient) which is to be administered is reached. Preferably, a pharmaceutically / therapeutically effective dose refers to that amount of the compound administered which, for example, results in amelioration (of symptoms) of and / or curation from the disease, in an improved condition and / or in a prolongation of survival of a subject. This can be determined by the one skilled in the art by routine testing. The dosage regimen of the pharmaceutical composition(s) / grafted cyclotide(s) to be administered in accordance with the invention will be determined by the attending physician and clinical factors. As is well known in the medical arts, dosages for any one patient depends upon many factors, including the patient's size, body surface area, age, sex, general health etc., the particular compounds to be administered, time and route of administration, and / or other drugs being administered concurrently. A person skilled in the art is aware of, will / can determine and is able to test the relevant doses, routes of administration and administration schemes of the compounds to be medically applied in accordance with the present invention. In accordance with the invention, the active agent (grafted cyclotide) may, for example, be administered at a dose in a range of 0.01 µg / kg BW to 100 mg / kg BW, 0.1 µg / kg BW to 100 mg / kg BW, 1 µg / kg BW to 100 mg / kg BW, 10 µg / kg BW to 100 mg / kg BW, 200 µg / kg BW to 60 mg / kg BW, 400 µg / kg BW to 40 mg / kg BW, 600 µg / kg BW to 20 mg / kg BW, or in a range of 800 µg / kg BW to 10 mg / kg BW. Other dose ranges may be up to 20 mg / kg BW. This may include even low doses (e.g. ≤0.01 µg / kg BW, ≤0.1 µg / kg BW, ≤1 µg / kg, ≤10 µg / kg). Of course, as mentioned, the doses may vary depending on the administration scheme and / or administration route. For example, if administered i.v., the doses are usually lower as compared to a p.o. administration. Non-limiting examples of possible doses in the context of p.o. administration are doses in a range of 10 µg / kg BW to 100 mg / kg BW, preferably in a range of 200 µg / kg BW to 60 mg / kg BW, more preferably in a range of 400 µg / kg BW to 40 mg / kg BW. Non-limiting examples of possible doses in the context of i.v. administration are doses in a range of 600 µg / kg BW to 20 mg / kg BW, preferably in a range of 800 µg / kg BW to 10 mg / kg BW. Doses in the range of up to 20 mg / kg BW may, for example, be appropriate and safe in the context of all three, p.o., i.p. and i.v. administration. This also may include even low doses (e.g. ≤0.01 µg / kg BW, ≤0.1 µg / kg BW, ≤1 µg / kg, ≤10 µg / kg). A dose / doses in accordance with the invention may be administered on a daily, weekly or monthly basis. The grafted cyclotide may be administered in form of 1 or more single doses (e.g. 1 or more single bolus); in particular, 1, 2, 3, 4 or 5 single doses (e.g. per day, week or month). A particular, however non-limiting, example is the administration of a single dose (of up to) 3 times a week. Continuous administration is also envisaged in the context of the invention. The grafted cyclotide may, for example, be administered subcutaneously, intravenously, intraperitoneally or orally. Thus, in the context of a non-limiting embodiment, a grafted cyclotide, or a pharmaceutical composition comprising it, is administered s.c., i.v., i.p. or orally, is formulated for s.c., i.v., i.p. or oral administration and / or comprises a pharmaceutically acceptable carrier for s.c., i.v., i.p. or oral administration. A non-limiting example of a particular administration scheme are 3 single s.c. or i.p. injections of up to 10 mg / kg BW at weekly intervals, for example in PBS. This may include low doses (e.g. ≤0.01 µg / kg BW, ≤0.1 µg / kg BW, ≤1 µg / kg, ≤10 µg / kg). Another non-limiting example of a particular administration scheme are 3 single oral administrations of up to 50 mg / kg BW at weekly intervals, for example in PBS. Also this may include low doses (e.g. ≤0.01 µg / kg BW, ≤0.1 µg / kg BW, ≤1 µg / kg, ≤10 µg / kg). Further possible administration schemes are described herein elsewhere. A preferred, however non-limiting, mode of administration scheme is peroral administration; and / or mode of administration which results in a pharmaceutical effect in the gut, (small and / or large) intestine, bowel. The grafted cyclotide may be comprised in the respective pharmaceutical composition or kit as the sole active ingredient, or together with (an)other (active) ingredient(s). The herein described pharmaceutical composition or kit may comprise also one or more of the herein disclosed grafted cyclotides (e.g. 2, 3, 4, 5 or more). Likewise, one or more of the herein disclosed grafted cyclotide may be administered in the context of the treatment methods disclosed herein. Specifically, the herein described pharmaceutical composition or kit may comprise at least two, three, four or five of the herein disclosed grafted cyclotides, and at least two, three, four or five of the herein disclosed grafted cyclotides may be administered, respectively. The herein described two or more grafted cyclotides, or grafted cyclotide and one or more further (active) agent(s), may be administered together, i.e. simultaneously, at the same or different administration sites and / or by the same or different administration routes; or they may be administered subsequently, at the same or different administration sites and / or by the same or different administration routes. In the latter case, the grafted cyclotide(s) may be administered first, followed by a subsequent administration of another agent, or the other agent may be administered first, followed by a subsequent administration of the cyclized grafted cyclotide(s). In one specific embodiment, the herein described pharmaceutical composition may further comprise one or more additional (active) agent(s) (in addition to the grafted cyclotide(s)). Likewise, the herein described (pharmaceutical composition comprising the) cyclized grafted cyclotide(s) may be co-administered with one or more additional (active) agent(s). The herein described grafted cyclotide(s) may also be used / administered in the context of a combination therapy or co-therapy, e.g. with or without one or more additional (active) agent(s). In another specific embodiment, the additional (active) agent(s) is (are) administered separately (temporary and / or spatially). The herein described (pharmaceutical composition comprising the) grafted cyclotide(s) may be administered together with one or more additional (active) agent(s), i.e. prior, simultaneously or subsequently with respect to the administration of the additional active agent(s). Non-limiting examples of one or more additional active agent(s) may be selected from the group consisting of KOR agonists (e.g. https: / / www.guidetopharmacology.org / GRAC / ObjectDisplayForward?objectId=318&familyId= 50&familyType=GPCR) and / or (other) pain or anti-inflamation therapeutics. The pharmaceutical composition of the invention may comprise (a) pharmaceutically acceptable carrier(s), excipient(s) or diluent(s). The pharmaceutical composition or grafted cyclotide of the invention may also be administered together with (a) pharmaceutically acceptable carrier(s), excipient(s) or diluent(s). Respective carriers, excipients or diluents are well known in the art. The skilled person is readily in the position to choose carriers, excipients or diluents which are suitable to be employed in accordance with the present invention. Pharmaceutically acceptable carriers / excipients / diluents (that may be used in the formulation of the pharmaceutical compositions comprising the active compounds as defined herein (or a salt thereof, or the like)) may generally comprise carriers, vehicles, diluents, solvents such as monohydric alcohols such as ethanol, isopropanol and polyhydric alcohols such as glycols and edible oils such as soybean oil, coconut oil, olive oil, safflower oil cottonseed oil, oily esters such as ethyl oleate, isopropyl myristate, binders, adjuvants, solubilizers, thickening agents, stabilizers, disintergrants, glidants, lubricating agents, buffering agents, emulsifiers, wetting agents, suspending agents, sweetening agents, colourants, flavours, coating agents, preservatives, antioxidants, processing agents, drug delivery modifiers and enhancers such as calcium phosphate, magnesium state, talc, monosaccharides, disaccharides, starch, gelatine, cellulose, methylcellulose, sodium carboxymethyl cellulose, dextrose, hydroxypropyl-ß- cyclodextrin, polyvinylpyrrolidone, low melting waxes, ion exchange resins. These and other suitable pharmaceutically acceptable carriers / excipients are, for example, described in Remington`s Pharmaceutical Sciences, 15thEd., Mack Publishing Co., New Jersey (1991). The nature of the pharmaceutically acceptable carrier / excipient / diluent may be so that the active agent(s) are released in a slow or retarded manner. Carriers, e.g. for oral administration, enable the compounds according to the present invention to be formulated as tablets, pills, capsules, dragees, liquids, gels, syrups, slurries, suspensions and the like, in particular for oral ingestion by a subject to be treated. In the context of the invention, “treating” / ”treatment” is, if not indicated otherwise, generally envisaged to encompass both, therapy and prevention / prophylactic treatment. Therapy may result in amelioration (of (a) symptom(s) of) or even in curing / healing the disease / disorder). A "patient" / ”subject” in the context of the purposes of the present invention, i.e. to whom (a) pharmaceutical composition(s) or grafted cyclotide(s) according to the present invention is to be administered and / or who suffers from the disease or disorder and / or symptom(s), and / or condition, as defined and described herein, in general includes both, humans and animals, as well as other organisms. Thus, the compositions and methods of this invention are applicable to, or in connection with, both, human treatments and veterinary applications, including treating and preventing procedures and methods. Preferably, the patient / subject is a mammal, and most preferably, the patient / subject is a human. The pharmaceutical composition, grafted cyclotide(s) / active ingredient(s), kit / kit of contents / kit of parts etc. of the invention may be comprised in, may be a part of and / or may be a medical device, a medicinal product packaging or pharmaceutical composition packaging. Such device or packaging may, for example, comprise or be (a) vial(s) / (a)container(s), (a) syringe(s) or (a) blister pack(s). The active ingredient(s), and pharmaceutical composition(s), respectively, may be comprised in the device or packaging separately and independently (e.g. in different vials / containers or syringes or blisters), or they may be comprised in combination (e.g. in the same vial(s) / container(s) or syringe(s) or blister(s)). Any of the pharmaceutical compositions, grafted cyclotides / active ingredients, kits etc. of the invention may be provided together with an instruction manual or instruction leaflet. The instruction manual / leaflet may comprise guidance for the skilled person / attending physician (on how) to treat or prevent a disease, disorder or symptom as described herein in accordance with the invention, for example pain and / or inflammation. In particular, the instruction manual / leaflet may comprise guidance as to the herein described mode of administration / administration regimen (for example route of administration, dosage regimen, time of administration, frequency of administration, etc.). In principle, what has been said herein elsewhere with respect to the mode of administration / administration regimen may be comprised as (an) instruction(s) in the instruction manual / leaflet. The present invention further relates to a method of preparing a grafted cyclotide, in particular a kB1-derived grafted cyclotide. In this context, the folding of the respective CK is to be performed prior to the grafting / insertion of the graft (the ‘plug and play’ approach described herein). Further, in the context of this method, a grafting scaffold, and / or respective peptide backbone, of the invention is to be used. The present invention also relates to a respective method of preparing the grafted cyclotide of the invention; and also a respective method of preparing the respective grafting scaffolds, peptide backbones and grafts. Also in this context, the grafting scaffold of the invention (and / or respective peptide backbone) may be used. The present invention further relates to a method of preparing a grafting scaffold of the invention. In the context of the methods of preparing as disclosed herein, it is preferred that the respective grafted cyclotides, grafting scaffolds and peptide backbones comprise the E3Q mutation as defined herein. The method of preparing the grafted cyclotide of the invention may comprise (e.g. as a step prior to a (oxidative) folding step and step of cyclization)) a step of generating the (linear) peptide backbone. Means and methods of generating a (linear) peptide are well known in the art and are, for example, described in Cheneval (J. Org. Chem.79, 2014, 5538-44) and herein elsewhere (see also Example 1, “Peptide synthesis…”). The (linear) peptide backbones of the grafted cyclotides, grafting scaffolds, grafts of the invention and as described herein may be produced by recombinant engineering techniques. Such techniques are well known in the art (e.g. Sambrook, supra). By this kind of production of the (linear) peptide backbones, nucleic acid molecules and / or vectors encoding the (linear) peptide backbones, and / or host cells comprising the nucleic acid molecules and / or vectors, may be used. The present invention also relates to respective (linear) peptide backbones, nucleic acid molecules, vectors and host cells. The (linear) peptide backbones of the grafted cyclotide(s), grafting scaffolds, grafts to be produced may also conveniently be produced by non-recombinant (chemical) peptide synthesis techniques. Several approaches of such peptide synthesis are known in the art. (e.g. Williams, Chemical Approaches to the Synthesis of Peptides, CRC-Press 1997; Benoiton: Chemistry of Peptide Synthesis. CRC-Press, 2005). The (linear) peptide backbones and (cyclic) peptides disclosed herein may, for example, be generated / synthesized as described in Example 1, “Peptide synthesis…”, below). The skilled person is, on the basis of the present disclosure and the common general knowledge, readily in the position to apply the prior art knowledge to the disclosed methods for preparing the grafted cyclotide, grafting scaffolds, peptide backbones, grafts of the invention, respectively, e.g. based on the herein provided teaching. In particular, with respect to the ‘plug and play’ approach to be applied in this context, the skilled person can rely on the respective guidance provided herein and in the appended experimental part and figures. In particular, the method for preparing a grafted cyclotide (or respective grafting scaffold) in accordance with the invention may comprise at least one, two or three, preferably all four, of the following steps (preferably in this order) and most preferably with step (iv) performed after step (ii), core aspect of the ‘plug and play’ approach) (i) preparing / providing a peptide backbone derived from kB1 in form of a linear peptide, wherein said peptide backbone comprises the six conserved Cys residues (CI-VI) of kB1; (ii) allowing said six conserved C residues to form three disulfide-bridges (so as to form a cystine knot motif (of kB1); i.e. CIand CIVform a disulfide-bridge, CIIand CVform a disulfide- bridge, and CIIIand CVIform a disulfide-bridge). Thereby the / a grafting scaffold is formed (this step corresponds to the folding step of the ‘plug and play’ approach); (iii) preparing / providing said dynA sequence in form of a linear peptide (the graft); and / or (iv) allowing said grafting scaffold of / as formed in (ii) to assemble / ligate with said dynA sequence (the graft) of / as prepared / provided in (iii), so as to cyclize said grafting scaffold with said dynA sequence to form said grafted cyclotide (including the formation of the CCK motif). In the context of step (i) and / or step (iii), above, said peptide backbone may be synthesized by (Fmoc or Boc) Solid Phase Peptide Synthesis ((Fmoc or Boc) SPPS ) and / or said dynA sequence may be synthesized by (Boc) Solid Phase Peptide Synthesis ((Boc) SPPS). In the context of step (ii), above, said disulfide-bridges may be formed by oxidation / oxidative folding (e.g. by using NH4HCO3buffers). The method preparing of the invention may further comprise the following step (iii´) protecting said dynA sequence, in particular its N-terminus (e.g. by Boc-protection) and / or its side-chains in need of protection (like any comprised lysine (K) residue(s) (e.g. by ivDde protection), any comprised tyrosine (Y) residue(s) (e.g. by tBu protection), any comprised arginine (R) residue(s) (e.g. by Pbf protection)). In the context of the preparing method of the invention, the grafting scaffold and / or dynA sequence may be prepared / provided as C-terminal acids. In the context of the preparing method according to the invention, in step (iv), (a) the N-terminus of said grafting scaffold may be (first) ligated with the C-terminus of said dynA sequence (with a (Boc-)protected N-terminus and with protected side-chains (e.g. as defined herein elsewhere)); (b) the ligated dynA sequence may be deprotected; and( / or) (c) the C-terminus of said grafting scaffold is (afterwards) ligated with the (deprotected) N- terminus of said dynA sequence (this is the ring closure / cyclization step which results in the final grafted cyclotide). In the context of the preparing method according to the invention, in step (iv), 2-(7-Aza-1-H- benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU) and / or N,N- Diisopropylethylamine (DIPEA) may be used. The herein disclosed methods of preparing the grafting scaffold of the invention may comprise the steps (i) and (ii) as described above; and as illustrated in the appended examples. The herein disclosed methods of preparing the peptide backbone of the grafting scaffold of the invention may comprise step (i) as described above and as illustrated in the appended examples. In the context of the preparing methods as disclosed herein, (further) optimizations may be performed. For example, in the context of the (oxidative) folding step (cf. Example 2; cf. item (ii), above), optimized conditions may be 0.2-0.5 mg / mL peptide in (about) 20% 0.1 M NH4HCO3, (about) 80% 2-propanol, (about) 1mM GSSG, e.g. at pH ~8.5, e.g. at 4 °C, for, e.g., 48-96 hours. Further, repeated addition of fresh redux reagens may be applied. For example, the fresh addition of, for example, oxidized glutathione may be performed; for example every (about) 24 hours, for example, over 96 hours. Respective guidance can also be found in the appended Example 2 and Example 10. For example, particularly in the context of the cyclization step, different coupling reagents (e.g., DIC / Oxyma) may be used. They may further reduce a potential risk of epimerization during amide bond formation between unprotected amino acids, particularly during the final cyclization step. In addition, the (optional) introduction of C-terminal glycine residues may fully circumvent epimerization problems. In principle, the herein disclosed and described method of preparing may also be applied and adapted to the preparing of any other grafted cyclotide (and also to the preparing of the respective other grafting scaffolds, peptide backbones and grafts). In one aspect, the present invention also relates to such (applied / adapted) method of preparing other grafted cyclotides / grafting scaffolds / peptide backbones / grafts. The present invention also relates to a grafting scaffold or a peptide backbone as defined herein elsewhere, to a grafting scaffold and a CK motif as defined herein elsewhere, and to a peptide backbone as comprised in a grafting scaffold and a CK motif as defined herein elsewhere, and to a grafted cyclotide, grafting scaffold and peptide backbone as obtained by any of the preparing methods as disclosed herein. As used herein, in particular with respect to the disclosed structures and methods of preparing, the terms "optional", "optionally" and "may" denote that the indicated feature may be present but can also be absent. Whenever the term "optional", "optionally" or "may" is used, the present invention specifically relates to both possibilities, i.e., that the corresponding feature is present or, alternatively, that the corresponding feature is absent. For example, the expression "X is optionally substituted with Y" (or "X may be substituted with Y") means that X is either substituted with Y or is unsubstituted. Likewise, if a component of a composition is indicated to be "optional", the invention specifically relates to both possibilities, i.e., that the corresponding component is present (contained in the composition) or that the corresponding component is absent from the composition. It is to be understood that where a list of groups is preceded by the expression "optionally substituted", the expression "optionally substituted" applies to each one of the respective groups in that list, not just to the first item in the list. As used herein, unless explicitly indicated otherwise or contradicted by context, the terms "a", "an" and "the" are used interchangeably with "one or more" and "at least one". Thus, for example, a composition comprising "a" compound of the present invention can be interpreted as referring to a composition comprising "one or more" compounds of the present invention. As used herein, the term "comprising" (or "comprise", "comprises", "contain", "contains", or "containing"), unless explicitly indicated otherwise or contradicted by context, has the meaning of "containing, inter alia", i.e., "containing, among further optional elements, …". In addition thereto, this term also includes the narrower meanings of "consisting essentially of" and "consisting of". For example, the term "A comprising B and C" has the meaning of "A containing, inter alia, B and C", wherein A may contain further optional elements (e.g., "A containing B, C and D" would also be encompassed), but this term also includes the meaning of "A consisting essentially of B and C" and the meaning of "A consisting of B and C" (i.e., no other components than B and C are comprised in A). As used herein, the terms "about", “similar”, or “slight(ly)” different etc., unless explicitly indicated otherwise or contradicted by context, has the meaning of ± ≤20%, ± ≤10%, ± ≤5%, ± ≤3%, ± ≤2% or ± ≤1%. In principle, the lower values are preferred in this respect. The present invention also relates to the following items: 1. A grafted cyclotide comprising (I) a cyclic cystine knot (CCK), in particular a CK, derived from kalata B1 (kB1; SEQ ID NO: 1); and (II) an amino acid sequence derived from dynorphin A (dynA sequence), wherein said dynA sequence is comprised in (i) the inter-cysteine loop 3 of said CCK (loop 3); (ii) the inter-cysteine loop 5 of said CCK (loop 5); or (iii) the inter-cysteine loop 6 of said CCK (loop 6). 2. The grafted cyclotide according to item 1, wherein said CCK / CK comprises a peptide backbone derived from kB1 or from a mutant of kB1 (for example from an Glu3Gln kB1 mutant ([E3Q]kB1; SEQ ID NO: 2) and / or a Thr20Lys kB1 mutant ([T20K]kB1; SEQ ID NO: 45). 3. The grafted cyclotide according to item 1 or 2, wherein the inter-cysteine loop 1 of said CCK (loop 1) comprises a Gln residue (Q), for example at amino acid position 2 of loop 1 (corresponding to amino acid position 3 in SEQ ID NO: 1 and 2). 4. The grafted cyclotide according to any one of items 1 to 3, wherein loop 1 comprises a mutation which corresponds to the mutation Glu3Gln (E3Q) in SEQ ID NO: 2. 5. The grafted cyclotide according to any one of items 1 to 4, wherein loop 1, the inter- cysteine loop 2 of said CCK (loop 2) and / or the inter-cysteine loop 4 of said CCK (loop 4) is native loop 1 (optionally except the mutation as defined in item 3 or 4), native loop 2 and / or native loop 4, respectively, of kB1. 6. The grafted cyclotide according to any one of items 1 to 5, wherein loop 4 comprises or consists of a Thr residue (T). 7. The grafted cyclotide according to any one of items 1 to 6, wherein loop 6 comprises at least the first and / or the last amino acid residue(s) of native loop 6 of kB1. The grafted cyclotide according to any one of items 1 to 7, wherein the dynA sequence as comprised in loop 6 is flanked by at least the first and / or the last amino acid residue(s) of native loop 6 of kB1. The grafted cyclotide according to item 7 or 8, wherein said first and / or last amino acid residue(s) of native loop 6 of kB1 is / are a Thr residue (T) and / or a Val residue (V), respectively. The grafted cyclotide according to any one of items 1 to 9, wherein loop 3 comprises at least the first and / or the last amino acid residue(s) of native loop 3 of kB1. The grafted cyclotide according to any one of items 1 to 10, wherein the dynA sequence as comprised in loop 3 is flanked by at least the first and / or the last amino acid residue(s) of native loop 3 of kB1. The grafted cyclotide according to item 10 or 11, wherein said first and / or last amino acid residue(s) of native loop 3 of kB1 is / are an Asn residue (N) and / or a Gly residue (G), respectively. The grafted cyclotide according to any one of items 1 to 12, wherein loop 5 comprises at least the first and / or the last amino acid residue(s) of native loop 5 of kB1. The grafted cyclotide according to any one of items 1 to 13, wherein the dynA sequence as comprised in loop 5 is flanked by at least the first and / or the last amino acid residue(s) of native loop 5 of kB1. The grafted cyclotide according to item 13 or 14, wherein said first and / or last amino acid residue(s) of native loop 5 of the cyclotide amino acid backbone is / are a Ser residue (S) and / or a Val residue (V), respectively. The grafted cyclotide according to any one of items 1 to 15, wherein said dynA sequence replaces loop 3, loop 5 or loop 6, respectively, preferably except the first and( / or) the last amino acid residue(s) of native loop 3, loop 5 or loop 6, respectively, of kB1. The grafted cyclotide according to any one of items 1 to 16, wherein said grafted cyclotide does not consist of a grafted cyclotide selected from the group consisting of: (i) cyclo-CGETCVGGTCNTPGCKCYGGFLRRIVCTRNGLPV (T20K-DYN 1; SEQ ID NO: 42); (ii) cyclo-CGETCVGGTCNTPGCKCSWPVCYGGFLRRIRPKLK (T20K-DYN 2; SEQ ID NO: 43); (iii) cyclo-CGETCVGGTCYGGFLRRIRPKLKCKCSWPVCTRNGLPV (T20K-DYN 3; SEQ ID NO: 44); and (iv) cyclo-YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT (∆L6[E3Q]kB1-dynA; SEQ ID NO: 5), or wherein said grafted cyclotide does not comprise an amino acid sequence selected from the group consisting of the amino acid sequences as depicted in (i), (ii), (iii) and (iv). The grafted cyclotide according to any one of items 1 to 17, wherein said dynA sequence consists of (or comprises) at least (the first) 8 (preferred), 9 (preferred), 10, 11 (preferred), 12 or 13 (preferred) (consecutive) amino acid residues of the amino acid sequence YGGFLRRIRPKLK (SEQ ID NO: 36); or at least (the first) 8, 9, 10, 11, 12 or 13 (consecutive) amino acid residues of the amino acid sequence YGGFLRRIRPKLK (SEQ ID NO: 36) having 1, 2, 3, 4, 5, 6, 7, or 8 (conservative) amino acid substitution(s), for example having 1, 2, 3 or 4 of Arg7, Ile8, Pro10 and Lys11 (conservatively) substituted (e.g. by Me-Arg7, D-Arg 7, D-Ile8, Dap, D-Pro10, Dap, Me-Lys11 and / or D-Lys11, respectively). The grafted cyclotide according to any one of items 1 to 18, wherein said dynA sequence consists of (or comprises) an amino acid sequence selected from the group consisting of: (i) YGGFLRRIRPKLK (SEQ ID NO: 36; most preferred). (ii) YGGFLRRI (SEQ ID NO: 37; preferred); (iii) YGGFLRRIR (SEQ ID NO: 38; preferred); (iv) YGGFLRRIRP (SEQ ID NO: 39); (v) YGGFLRRIRPK (SEQ ID NO: 40; preferred); and (vi) YGGFLRRIRPKL (SEQ ID NO: 41). The grafted cyclotide according to any one of items 1 to 19, wherein said grafted cyclotide comprises an amino acid sequence selected from the group consisting of: (i) GCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 33; kB1-derived backbone of, for example, ^L3[E3Q]kB1-dynA or ∆L3[E3Q]kB1-dynA3.4); (ii) VCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 34; kB1-derived backbone of, for example, ^L5[E3Q]kB1-dynA or ∆L5[E3Q]kB1-dynA2.4); and (iii) VCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 35; kB1-derived backbone of, for example, ^L6[E3Q]kB1-dynA or ∆L6[E3Q]kB1-dynA1.4). The grafted cyclotide according to any one of items 1 to 20, wherein said grafted cyclotide comprises an amino acid sequence selected from the group consisting of: (i) YGGFLRRIRPKLKGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 18; backbone of ^L3[E3Q]kB1-dynA; SEQ ID NO: 19; backbone of ∆L3[E3Q]kB1-dynA3.4); (ii) YGGFLRRIRPKLKVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 20; backbone of ^L5[E3Q]kB1-dynA; SEQ ID NO: 21; backbone of ∆L5[E3Q]kB1-dynA2.4); (iii) YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 22; backbone of ^L6[E3Q]kB1-dynA; SEQ ID NO: 23; backbone of ∆L6[E3Q]kB1-dynA1.4); (iv) YGGFLRRIRPKGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 24; backbone of ^L3[E3Q]kB1-dynA3.1); (v) YGGFLRRIRGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 25; backbone of ^L3[E3Q]kB1-dynA3.2); (vi) YGGFLRRIGCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 26; backbone of ^L3[E3Q]kB1-dynA3.3); (vii) YGGFLRRIRPKVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 27; backbone of ^L5[E3Q]kB1-dynA2.1); (viii) YGGFLRRIRVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 28; backbone of ^L5[E3Q]kB1-dynA2.2); (ix) YGGFLRRIVCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 29; backbone of ^L5[E3Q]kB1-dynA2.3); (x) YGGFLRRIRPKVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 30; backbone of ^L6[E3Q]kB1-dynA1.1); (xi) YGGFLRRIRVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 31; backbone of ^L6[E3Q]kB1-dynA1.2); and (xii) YGGFLRRIVCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 32; backbone of ^L6[E3Q]kB1-dynA1.3). The grafted cyclotide according to any one of items 1 to 21, which is a grafted cyclotide selected from the group consisting of: (i) cyclo-YGGFLRRIRPKLKGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA; SEQ ID NO: 3; SEQ ID NO: 9; ∆L3[E3Q]kB1-dynA3.4); (ii) cyclo-YGGFLRRIRPKLKVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA; SEQ ID NO: 4; SEQ ID NO: 13; ∆L5[E3Q]kB1-dynA2.4); (iii) cyclo-YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA; SEQ ID NO: 5; SEQ ID NO: 17; ∆L6[E3Q]kB1-dynA1.4); (iv) cyclo-YGGFLRRIRPKGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.1; SEQ ID NO: 6); (v) cyclo-YGGFLRRIRGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.2; SEQ ID NO: 7); (vi) cyclo-YGGFLRRIGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.3; SEQ ID NO: 8; (vii) cyclo-YGGFLRRIRPKVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.1; SEQ ID NO: 10); (viii) cyclo-YGGFLRRIRVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.2; SEQ ID NO: 11); (ix) cyclo-YGGFLRRIVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.3; SEQ ID NO: 12); (x) cyclo-YGGFLRRIRPKVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.1; SEQ ID NO: 14); (xi) cyclo-YGGFLRRIRVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.2; SEQ ID NO: 15); and (xii) cyclo-YGGFLRRIVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.3; SEQ ID NO: 16). The grafted cyclotide according to any one of items 19 to 22, wherein said amino acid sequence has one or more of the (conservative) amino acid substitution(s) as defined in item 18. The grafted cyclotide according to any one of items 1 to 23, wherein said grafted cyclotide (a) (fully or partially) activates the kappa opioid receptor (KOR) (i.e. said grafted cyclotide is a (full or partial) KOR agonist; e.g. with an ECmax in the range of 80- 170%, preferably in the range of 100-150% (as compared to Dynorphin A 1-13 (100%)) and / or with a potency / efficacy (cAMP) in the range of 10 nM to 130nM, preferably in the range of 20 nM to 120 nM; activation and potency / efficacy (cAMP) may be determined by a functional cAMP inhibition assay (e.g. as disclosed in the appended Examples and in Muratspahic, J. Med. Chem.64, 2021, 9042-55); e.g. ECmaxmay be about 109% and / or potency / efficacy (cAMP) may be about 28 nM for the grafted cyclotide as defined in item 1(i) and subsequent items 2 to 23; ECmaxmay be about 128% and / or potency / efficacy (cAMP) may be about 112 nM for the grafted cyclotide as defined in item 1(ii) and subsequent items 2 to 23; ECmaxmay be about 139% and / or potency / efficacy (cAMP) may be about 69 nM M for the grafted cyclotide as defined in item 1(iii) and subsequent items 2 to 23); and / or (b) binds to KOR at a nanomolar affinity (like an affinity corresponding to a Ki in the range of 0.5 nM to 10 nM, preferably in the range of 1.0 nM to 7 nM; e.g. to a Ki value of about 1.4 nM for the grafted cyclotide as defined in item 1(i) and subsequent items 2 to 23; to a Ki value of about 3.2 nM for the grafted cyclotide as defined in item 1(ii) and subsequent items 2 to 23; to a Ki value of about 6.2 nM for the grafted cyclotide as defined in item 1(iii) and subsequent items 2 to 23; affinity may be determined by a radioligand competition binding assay (e.g. as disclosed in the appended Examples and in Muratspahic, J. Med. Chem. 64, 2021, 9042-55)). A pharmaceutical composition comprising the grafted cyclotide according to any one of items 1 to 24, and optionally a pharmaceutically acceptable carrier. A pharmaceutical composition comprising the grafted cyclotide according to any one of items 1 to 24, and optionally a pharmaceutical carrier, for use in (i) treating (peripheral) inflammation (e.g. inflammatory bowel disease (IBD), like ulcerative colitis or Crohn's disease); and / or (ii) treating (chronic) (peripheral) pain, e.g. (chronic) abdominal pain, (chronic) visceral pain, (chronic) peripheral neuropathic pain, diarrhea, rectal bleeding, fatigue and / or weight loss, in particular (chronic) (peripheral) pain, e.g. (chronic) abdominal pain, (chronic) visceral pain, (chronic) peripheral neuropathic pain, diarrhea, rectal bleeding, fatigue and / or weight loss relating to / coming along with (i); and / or (ii) treating itching and / or disorders associated with itching. The pharmaceutical composition according to item 25 or the pharmaceutical composition for use according to item 26, wherein said grafted cyclotide or said pharmaceutical composition is (to be) administered systemically. The pharmaceutical composition according to item 25 or 27 or the pharmaceutical composition for use according to item 26 or 27, wherein said grafted cyclotide or said pharmaceutical composition is (to be) administered parenterally (e.g. s.c.; i.v.; i.m.; i.a.), perorally (preferred; e.g. in form of tablets; pills; capsules; powders; solutions; suspensions), rectally (e.g. by suppository) or bronchially (e.g. by inhalation (e.g. of a spray; aerosol; via a nebulizer; via an inhaler)). The grafted cyclotide or the pharmaceutical composition according to any one of items 1 to 28, wherein said grafted cyclotide and / or said pharmaceutical composition is for use in a method for treatment. A method of producing a pharmaceutical composition according to any one of items 25 to 29, said method comprising the step of admixing a grafted cyclotide as defined in any one of items 1 to 24 and a pharmaceutically acceptable carrier. A method of preparing a kB1-derived grafted cyclotide, in particular the grafted cyclotide according to any one of items 1 to 24, said method comprising the following steps (most preferably with step (iv) performed after step (ii)) (i) preparing / providing a peptide backbone derived from kB1 in form of a linear peptide, wherein said peptide backbone comprises the six conserved Cys residues (CI-VI) of kB1; (ii) allowing said six conserved C residues to form three disulfide-bridges (so as to form a cystine knot motif (of kB1); i.e. CIand CIVform a disulfide-bridge, CIIand CV form a disulfide-bridge, and CIII and CVI form a disulfide-bridge), thereby forming an / the (acyclic but folded) grafting scaffold; (iii) preparing / providing a / said dynA sequence in form of a linear peptide (the graft); (iv) allowing said grafting scaffold of (ii) to assemble / ligate with said dynA sequence (the graft) of (iii), so as to cyclize said grafting scaffold with said dynA sequence to form said grafted cyclotide (including the formation of the CCK motif). The method according to item 31, wherein in step (i) and / or step (iii) said peptide backbone is synthesized by (Fmoc or Boc) Solid Phase Peptide Synthesis ((Fmoc or Boc) SPPS) and / or said dynA sequence is synthesized by (Boc) Solid Phase Peptide Synthesis ((Boc) SPPS). The method according to item 31 or 32, wherein in step (ii) said disulfide-bridges are formed by oxidation / oxidative folding (e.g. by using NH4HCO3 buffers). The method according to any one of items 31 to 33, said method further comprising the following step (iii´) protecting said dynA sequence, in particular its N-terminus (e.g. Boc-protection) and / or its side-chains in need of protection (like any comprised lysine (K) residue(s) (e.g. ivDde protection), any comprised tyrosine (Y) residue(s) (e.g. tBu protection), any comprised arginine (R) residue(s) (e.g. Pbf protection)). The method according to any one of items 31 to 34, wherein said grafting scaffold and said dynA sequence are prepared / provided as C-terminal acids. The method according to any one of items 31 to 35, wherein in step (iv) (a) the N-terminus of said grafting scaffold is (first) ligated with the C-terminus of said dynA sequence (with a (Boc-)protected N-terminus and with protected side- chains (e.g. as defined in item 34)); (b) the ligated dynA sequence is deprotected; and (c) the C-terminus of said grafting scaffold is (afterwards) ligated with the (deprotected) N-terminus of said dynA sequence (the ring closure / cyclization resulting in the grafted cyclotide) . The method according to any one of items 31 to 36, wherein in step (iv) 2-(7-Aza-1-H- benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU) and N,N- Diisopropylethylamine (DIPEA) are used. A grafting scaffold or a peptide backbone as defined in item 31, a grafting scaffold comprising a CK motif as defined in any one of items 1 to 17 and 20 to 24, or a peptide backbone as comprised in a grafting scaffold comprising a CK motif as defined in any one of items 1 to 17 and 20 to 24, or a grafting scaffold or grafted cyclotide as obtained by a production method as disclosed herein; e.g. by the method of any one of items 31-37. The present invention is further described by reference to the following non-limiting figures and examples. The Figures show: Figure 1. Comparison of current synthetic methodologies for grafted cyclotide synthesis and the plug and play approach of the invention. A) Various Fmoc-SPPS based methods start with the linear grafted cyclotide that is first backbone cyclized (cyc) and then oxidized (ox). B) In the plug and play approach (p+p), grafted cyclotides are obtained by oxidizing the scaffold peptide (just “scaffold” in the figure) to reach the grafting scaffold prior to grafting of the epitope (the graft) to yield the cyclized peptide backbone and oxidized final product, respectively. Cysteine residues are numbered with Roman numerals, the dots in A) represent free thiols and the vertical lines represent the three disulfide bonds. Figure 2. Plug and play (p+p) synthesis. A) Plug and play (p+p) synthesis of kalata B1 (left) and [E3Q]kB1 (right). Analytical comparison of cyclic kB1 and [E3Q]kB1 confirming identity of products as shown by retention time (RT) analysis (B) and αH chemical shift comparison (C). L ligated product, E excess epitope, A acyclic starting material, C cyclic product, X unwanted side- product, *peak showing m / z of epitope minus one Da, #no m / z observed, black dots indicate side-chain protecting groups. In C), kB1 native, kB1 p+p, E3Q ctrl and E3Q p+p are from left to right in each group of the four respective bars. Figure 3. Comparison of folding of linear kB1 scaffold peptides. ‘Initial’ conditions (top panels) versus ‘optimized’ condition (bottom panels) for each scaffold. * denotes native fold, D denotes putative dimer, see Table 2 for calculated yields. Figure 4. Analytical HPLC and mass spectra of oxidized scaffold peptides (grafting scaffolds). For more details see Table 2 and Example 2. Figure 5. Analytical HPLC and mass spectra of epitope peptides (grafts). For more details see Table 3 and Example 3. Figure 6. Analytical HPLC monitoring of ‘plug and play’ grafting strategy of peptide L6-dynA. A) ligation reaction shows excess epitope (E), ligated product (L) and an additional m / z corresponding to the epitope minus one Da (1). B) Deprotection reaction showing acyclic product (A) and additional peak with m / z corresponding to deprotected epitope (2). C) Direct injection MS analysis of cyclization reaction shows one major product with m / z corresponding to cyclic peptide with lysine residues still side-chain protected C(ivDde). D) After hydrazine treatment one major peak with m / z corresponding to fully deprotected cyclic product (C) is observed. One additional peak with m / z corresponding to final product plus 32 Da is identified (3). Figure 7. Analytical HPLC and mass spectra of grafted peptide. For more details see Table 4 and Example 4. Figure 8. MALD-TOF MS comparison of native kB1 and the two products obtained from cyclization reaction. After one hour incubation, no change in the m / z of fully reduced and alkylated native kB1 (A) and the minor cyclization reaction product (B) was observed (* m / z 3238.0 Da [M+H]+). The major product (C) was readily digested until m / z 982.9 Da [M+H]+(D), corresponding to the cyclized fragment RNGLPVCGE (SEQ ID NO: 58). Figure 9.1H NMR spectra of acyclic oxidized scaffold peptides (grafting scaffold). The spectra were acquired at 600MHz, solvent H2O / D2O (9:1). For more details see Example 9. In the herein detailed description of the invention, a number of individual elements, characterizing features, techniques and / or steps are disclosed. It is readily recognized that each of these has benefit not only individually when considered or used alone, but also when considered and used in combination with one another. Accordingly, to avoid exceedingly repetitious and redundant passages, this description has refrained from reiterating every possible combination and permutation. Nevertheless, whether expressly recited or not, it is understood that such combinations are entirely within the scope of the presently disclosed subject matter. All technical and scientific terms used herein, unless otherwise defined, are intended to have the same meaning as commonly understood by one of ordinary skill in the art. Reference to techniques employed herein are intended to refer to the techniques as commonly understood in the art, including variations on those techniques or substitutions of equivalent techniques that would be apparent to one of skill in the art. In this specification, a number of documents including patent applications are cited. The disclosure of these documents, while not considered relevant for the patentability of this invention, is herewith incorporated by reference in its entirety. More specifically, all referenced documents are incorporated by reference to the same extent as if each individual document was specifically and individually indicated to be incorporated by reference. Reference is made herein also to the following amino acid sequences (and also to the respective coding nucleotide sequences, as the case may be). SEQ ID NO.1: kalata B1 (kB1; Oldenlandia affinis); cyclo-CGETCVGGTCNTPGCTCSWPVCTRNGLPV SEQ ID NO.2: Glu3Gln kB1 mutant ([E3Q]kB1); cyclo-CGQTCVGGTCNTPGCTCSWPVCTRNGLPV SEQ ID NO.45: Thr20Lys kB1 mutant ([T20K]kB1); cyclo-GLPVCGETCVGGTCNTPGCKCSWPVCTRN The invention will now be described by reference to the following examples which are merely illustrative and are not to be construed as a limitation of the scope of the present invention. Example 1: Peptide synthesis, cleavage, and RP-HPLC purification Peptides were synthesized by automated Fmoc SPPS on a Symphony peptide synthesizer (Protein Technologies) or a CS136X synthesizer (CS Bio). The following side-chain protecting groups were used: Cys(Trt), Cys(Acm), Glu(tBu), Lys(ivDde), Asn(Trt), Gln(Trt), Arg(Pbf), Ser(tBu), Thr(tBu), Trp(Boc) and Tyr(tBu). Peptides were assembled on 2-CTC resin (substitution value 0.45 or 1 mmol / g, 0.125 mmol synthesis scale). The first amino acid was coupled to the resin for 1 h in dichloromethane (DCM), with a 2-fold excess of amino acid and 8-fold excess of N,N-diisopropylethylamine (DIPEA). After coupling the resin was treated three times with a mixture of methanol:DCM:DIPEA (17:2:1) for one minute each to cap any remaining reactive functionalities on the resin. Fmoc deprotection was carried out with piperidine in DMF (20% (v / v)) twice for two minutes. Subsequent amino acids were coupled twice for 10 minutes using an amino acid / 2-(6-chloro-1-H-benzotriazol-1-yl)-1,1,3,3- tetramethylaminium hexafluorophosphate (HCTU) / DIPEA ratio of 4:4:8 relative to resin loading. DMF was used for resin washing between all steps. After chain assembly was completed, the resin was washed with DCM and dried under nitrogen. For concomitant cleavage of the peptide chain and side-chain removal, the dry resin was then treated with TFA:TIPS:H2O (90:5:5, v / v / v) for two hours, excess TFA was removed, and the peptides precipitated in ice-cold diethyl ether. The precipitate was filtered and dissolved in a 50:50 mixture of solvent A (0.1% TFA in water) and solvent B (90% acetonitrile, 0.1% TFA in water). N-terminally Boc- and side-chain protected peptides were obtained by treating the resin ten times with 1% TFA in DCM for four minutes each. A 50:50 mixture of solvent A and B was added, and DCM removed on a rotary evaporator. Crude peptides were then lyophilized prior to purification by RP-HPLC. Samples were purified using preparative and semipreparative RP-HPLC on a Shimdazu Prominence HPLC system on Phenomenex Gemini columns (5 μm C18110 Å, 250 x 21.2 or 10 mm respectively). Correct products were identified using ESI-MS on a Shimadzu 2020 or a SCIEX API2000 mass spectrometer. Purity of all compounds was assessed either by UPLC analysis using a Luna Omega C18 column (Phenomenex 1.6 μm, 100 Å, 50 x 2.1 mm) with a linear gradient of 1 to 61% B over 15 minutes on a Shimadzu Nexera UPLC system or analytical HPLC using an Agilent Zorbax column (Agilent 150 x 2.1 mm) on a Shimadzu Prominence HPLC system. A linear gradient of 5 to 80% solvent B over 35 minutes was used for unprotected peptides, for protected peptides a linear gradient of 50 to 100% solvent B over 30 minutes was used. Example 2: Oxidative folding scaffold peptides and characterization of the resulting grafting scaffolds Oxidation of peptides (Table 2) was achieved by dissolving peptides at a concentration of 0.2- 0.5 mg / mL in oxidation buffer (different ratios of 0.1 M NH4HCO3 and 2-propanol, pH 8.2-8.5, varying amounts of reduced and / or oxidized glutathione). Oxidized peptides were purified after overnight incubation (>18 hours at room temperature or 4 ⁰C). Initial folding buffer conditions: 0.2-0.5 mg / mL peptide in 50% 0.1 M NH4HCO3, 50% 2-propanol, 1mM GSH, pH ~8.5, 20 ⁰C for 24 hours. Final optimized conditions: 0.2-0.5 mg / mL peptide in 20% 0.1 M NH4HCO3, 80% 2-propanol, 1mM GSSG, pH ~8.5, 4 ⁰C for 48-96 hours. Example 3: Characterization of protected epitope peptides Linear epitope Boc-L6 (Table 3) was synthesized by the method reported in Example 1 using the side-chain protections Arg(Pbf), Asn(Trt) and purified by as in Example 1 and characterized by analytical HPLC and MS (Fig 5). Linear Dyn A epitope (Table 3) was synthesized by the method reported in Example 1 using the side-chain protections Arg(Pbf), Lys (ivDde) and Tyr(tBu) and purified by as in Example 1 and characterized by analytical HPLC and MS (Fig 5). Example 4: ‘plug and play’ grafting and characterization of cyclic peptides Ligation reactions (Fig.6A) were performed in DMF by pre-activating the protected epitope for at least 30 seconds using 4 eq of 2-(7-Aza-1-H-benzotriazole-1-yl)-1,1,3,3- tetramethyluronium hexafluorophosphate (HATU). Upon addition of at least 8 eq of DIPEA (added dropwise until solution turned yellow) the mixture was added to purified acyclic scaffold peptides (grafting scaffolds) to initiate the ligation reaction. For cyclization reactions (Fig.6C) a 1:1:2 molar ratio of peptide:HATU:DIPEA was used. Both protected as well as fully deprotected peptides were readily dissolved in DMF. Removal of ivDde from Lys residues (Fig. 6D) was achieved by treating the sample with 5% hydrazine in DMF for 10 minutes. Reactions were monitored using UPLC-MS on a Shimadzu Nexera and 2020 LCMS system or by direct injection MS analysis on a SCIEX API2000 mass spectrometer. Samples containing DMF were diluted at least 10 x with HPLC solvents prior to loading onto columns. Correct mass and purity was assessed as described under Example 1 (Fig.7, Table 4). No evidence for epimerization during amide bond formation between unprotected amino acids, particularly during the final cyclization step, was observed for the shown examples. The use of different coupling reagents (e.g., DIC / Oxyma) may, in any case, reduce the potential risk of epimerization during amide bond formation between unprotected amino acids, particularly during the final cyclization step; and introduction of C-terminal glycine residues may fully circumvent epimerization problems. Example 5: Carboxypeptidase Y digest and MALDI-TOF MS Aliquots of peptides (20µL of ~100µM) were reduced for 30 minutes at 60 ⁰C using DTT (final concentration of 20 mM) and alkylated for 15 minutes at room temperature with iodoacetamide (final concentration of 50 mM).0.5 units of carboxypeptidase Y were added to fully reduced and alkylated samples and incubated for one hour. Samples were desalted using C18 ZipTips prior to spotting on a MALDI stainless steel plate (mixed 1:1, v / v with a saturated solution of α-cyano-4-hydroxycinnamic acid). Spectra were acquired on a MALDI-TOF / TOF 5800 Analyzer (AB Sciex) operated in reflector positive mode. This experiment showed that a Glu->Gln replacement in position 3 (loop 1) of the scaffold peptides further abolishes major side-product and thus significantly increases yields of backbone cyclic product, i.e. the grafted cyclotide (see also Figure 8). Example 6: KOR pharmacology HEK293 cells were cultured in Dulbecco’s modified Eagle medium (DMEM) containing 10% fetal bovine serum and 50 U / mL penicillin and streptomycin and were grown at 37 °C and 5% CO2. The HEK293 cell line stably expressing mouse KOR-EGFP was generated by geneticin disulfate (0.8 mg / mL of G418, ROTH, Austria) selection and flow cytometry to select cells for stable cell line propagation. Positive clones were identified by radioligand binding studies as previously described (Muratspahić, J. Med. Chem.64, 2021, 9042-55). Example 7: Radioligand Competition Binding Assays Membranes were prepared from HEK293 cells stably expressing the KOR as previously described (Muratspahić, J. Med. Chem.64, 2021, 9042-55). Radioligand binding studies were carried out in duplicate using standard binding buffer containing 50 mM Tris−HCl (pH 7.4), 10 mM MgCl2, and 0.1% BSA. For competition binding, 75 μL each of [3H]-diprenorphine (1 nM final), peptide solution (4×), and membrane preparations (7 μg / assay) was incubated in the standard binding buffer, and binding reactions were incubated for 1 h at 37 °C. Termination of reactions was performed by rapid filtration onto a 0.1% polyethylenimine-soaked GF / C glass fiber filter with a Skatron cell harvester. Example 8: cAMP Assay Functional cAMP assay was conducted in triplicate using HEK293 cells stably expressing the mouse KOR according to the manufacturer’s protocol with slight modifications. Briefly, 2000 cells per 5 μL per well were seeded into a white 384-well plate and incubated with 5 μL of logarithmically spaced concentrations of peptide solutions prepared (2×) in 1× stimulation buffer and forskolin (10 μM final). The reaction mixture was incubated at 37 °C for 30 min followed by addition of Europium cryptate-labeled cAMP and cAMP d2-labeled antibodies (5 μL of each). After incubation for 1 h at room temperature, cAMP quantification was measured by homogenous time-resolved fluorescence resonance energy transfer on a Flexstation 3 (Molecular Devices, San Jose, USA) using a ratio of 665 / 620 nm. Example 9: NMR characterization Samples were prepared by dissolving ~0.5–1 mg of dry peptide in 0.5 mL of 90% H2O / 10% D2O (vol / vol). NMR experiments, including 1D, total correlation spectroscopy (TOCSY) and nuclear Overhauser effect spectroscopy (NOESY), were recorded on a Bruker Avance-600 MHz spectrometer at 298 K. Solvent suppression was achieved using pulse sequences with excitation sculpting (zgesgp, mlevesgpph and noesyesgpph). TOCSY and NOESY experiments were acquired with a mixing time of 80 and 200 ms respectively, 4,096 complex data points in the F2 dimension and 512 increments in the F1 dimension, and they were processed using TopSpin (Bruker Biospin) software. Chemical shifts were referenced to internal 2,2-dimethyl- 2-silapentane-5-sulfonate. Spectra were analyzed in CCPNMR software (Skinner, J. Biomol. NMR 66, 2016, 111-24). Example 10: Results and discussion (in particular concerning Examples 1-9) To verify first that a modular approach would work for the synthesis of cyclotides, the prototypic cyclotide kalata B1 (kB1) was synthesized via a two-fragment approach. As proof-of- concept, the previously reported acyclic peptide, des(24-28)kB1 (Barry, Biochemistry 42, 2003, 6688-95), was set out to be synthesized as a ‘receiver module’ (grafting scaffold) and the missing residues of the native loop 6, i.e. RNGLP, was subsequently engrafted into that sequence. The acyclic precursor des(24-28)kB1 (hereafter also referred to as ∆L6kB1) was successfully assembled via automated Fmoc-SPPS, folded and purified as previously described (Daly, J. Biol. Chem.275, 2000, 19068-75) (Fig. 3, 4 and 9. Then envisaged a two-step ligation protocol was applied to avoid self-cyclization of two peptide fragments with free amino and carboxy termini which may result in self-cyclization of the individual reaction partners. Using Fmoc-SPPS on hyper acid-labile 2-chlorotrityl chloride resin, a fully side-chain and N-terminally protected version of loop 6, i.e., Boc-R(Pbf)N(Trt)GLP-OH (Boc-L6; SEQ ID NO: 56), was generated to rule out self-cyclization and unwanted side reactions of the epitope. To further reduce the possible self-cyclization of the fully unprotected scaffold ∆L6kB1, and to favor ligation of the two fragments, a four-fold molar excess of the epitope Boc-L6 was used. The reaction between folded ∆L6kB1 and Boc-L6 (1 mM scaffold, 4:4:8 equivalents epitope:HATU:DIPEA) yielded the desired ligated peptide as a major product (67.8% isolated yield) (Fig.2A); without any evidence for self-cyclization of the scaffold ∆L6kB1. Further, LCMS analysis did not indicate racemization of the C-terminal proline and showed only the expected ligated product and excess epitope. Both peptides were readily recovered during subsequent HPLC purification of the ligation reaction. Next, the linear peptide was deprotected by applying standard side-chain deprotection conditions (TFA:TIPS:H2O, 90:5:5). The reaction proceeded efficiently and allowed recovery of fully deprotected linear kB1 (Fig. 2A). Finally, backbone cyclization was attempted by treating the linear peptide (1 mM) with HATU / DIPEA (1:2 eq) in DMF for one hour followed by HPLC purification. Analysis of the crude reaction after one hour revealed two major products, both exhibiting the expected m / z of the desired product (Fig.2A). Additional minor peaks present in the cyclization reaction could not be identified by LCMS analysis. Further characterization using carboxypeptidase Y digest revealed the early eluting major product (63%) to be an unwanted self-cyclization product between the free N-terminal amino group of arginine 24 and the side-chain carboxy group of the glutamic acid residue 3 (Fig. 8). The minor product (27%) was subjected to analysis using analytical HPLC as well as NMR. Co- injection of authentic kB1 or synthetic samples resulted in a sharp single peak on HPLC (Fig.2B). Similarly, secondary αH NMR chemical shifts of authentic kalata B1 and the late eluting minor product obtained from the cyclization reaction were identical, thus unambiguously confirming identity of the two samples (Fig.2C). Having established a successful plug and play methodology, a further optimization of the peptide backbone and respective grafting scaffold was set out for subsequent grafting applications. Since the presence of the glutamic acid residue seemed to favor some formation of an unwanted side-product, and thus somewhat reduced the yields of the desired cyclic product, possible substitutions of the glutamic residue were investigated. The full-length backbone cyclic version of [E3A]kB1 was previously shown to give some reasonable folding yields, ~50% compared to native kB1 (Simonsen, J. Biol. Chem.283, 2008, 9805-13). However, concomitant removal of loop 6 appears to somewhat perturb the folding of the peptide ∆L6[E3A]kB1, and only some amounts (~4%) of correctly folded peptide were observed (Fig.3). It was thus hypothesized that a more conservative replacement of the glutamic acid with glutamine might still be able to provide sufficient hydrogen bonding interactions to stabilize the native fold within the linear ∆L6kB1 sequence. The same folding conditions used for ∆L6kB1 also yielded correctly folded ∆L6[E3Q]kB1, with the correctly folded peptide being ~10%, and ~15% being a putative dimer. It was further investigated whether different buffers and the repeated addition of fresh redox reagents could help to increase folding yields (Leta Aboye, Chembiochem 9, 2008, 103-13). Indeed, fresh addition of oxidized glutathione every 24 hours helped to increase folding yields up to 16.6% over 96 hours and final optimized conditions afforded the desired product in isolated yields of >15% with only traces of dimer present (<2%) as assessed by RP-HPLC (Fig.3). Isolated oxidized ∆L6[E3Q]kB1 was then used to proceed with the plug and play methodology as described above for kB1 as such. Ligation of ∆L6[E3Q]kB1 (1 mM) with 4 equivalents of Boc-L6 and HATU:DIPEA (4:8 eq) in DMF for one hour as well as subsequent deprotection of the purified product using TFA:TIPS:H2O 90:5:5 for one hour both proceeded smoothly (53% and 94% isolated yields), and the purified linear deprotected peptide was subjected to final backbone cyclization for one hour using HATU:DIPEA (1:2 eq) in DMF. The major product (49% isolated yields) was a late eluting peak exhibiting the desired m / z corresponding to cyclic [E3Q]kB1. The peptide co-eluted with a sample that was obtained via a previously reported strategy (Cheneval, J. Org. Chem.79, 2014, 5538-44) confirming successful synthesis of [E3Q]kB1 via the plug and play approach (Fig.2B). Secondary chemical shift analysis confirmed that the mutation and chemical strategy does not disrupt the native structure of kB1 (Fig.2C). To verify the suitability of the plug and play approach and respective peptide backbones / grafting scaffolds for cyclotide grafting, a KOR ligand was synthesized. In particular, the effect of a kB1-derived scaffold on biological activity of the epitope sequence, the endogenous κ-opioid receptor ligand dynorphin A (1-13) (YGGFLRRIRPKLK; herein elsewhere also referred to as dynA), was determined. As previous attempts to graft dynA onto a kB1 scaffold using currently established protocols (Zheng, Chembiochem 13, 2012, 542-6; Cheneval, J. Org. Chem.79, 2014, 5538-44) were unsuccessful, an N-terminally protected version of dynA was synthesized, and the plug and play approach was applied to this version. It was envisaged that, besides protection of the N-terminal amino group using Boc for the initial ligation reaction, a selective protection of any side chain amino group in need of protection would be necessary for both, ligation and cyclization reactions. Thus, lysine residues protected with 1-(4,4- Dimethyl-2,6-dioxocyclohex-1-ylidene)-3-methylbutyl (ivDde) were used to prevent unwanted side product formation during these steps. Automated Fmoc-SPPS Synthesis of linear dynA was successful and HPLC purification yielded the fully protected peptide Boc- Y(tBu)GGFLR(Pbf)R(Pbf)IR(Pbf)PK(ivDde)LK(ivDde)-OH (SEQ ID NO: 57). As for kB1 and [E3Q]kB1, all steps proceeded smoothly, the full-length cyclic dynA grafted into loop 6 of [E3Q]kB1 was obtained with an overall yield of 17.4% over three steps (Fig. 6). The peptide was then tested using competitive radioligand binding assays, as well as functional activation using cAMP inhibition assays. ∆L6[E3Q]kB1-dynA showed nanomolar affinity and full agonist activity at the κ-opioid receptor (Table 1); comparable to the recently published peptide helianorphin-19 (Muratspahić, J. Med. Chem.64, 2021, 9042-55). The impact of grafting dynA into various other loops of the cyclotide scaffold was next explored. Since acyclic versions of kB1 that have been linearized in loops 2, 3, 5 and 6 have been shown to fold into a native cyclotide-like structure (Daly, J. Biol. Chem. 275, 2000, 19068-75), linear versions of [E3Q]B1 were synthesized without loops 2, 3 and 5 respectively, leaving only a single flanking amino acid on either side of the cysteine (Table 2, Fig. 4 and 9). All peptides were subjected to ‘standard’ as well as the ‘optimized’ folding conditions as determined for ∆L6[E3Q]kB1. Optimized conditions allowed us to obtain sufficient material for all linear ∆L#[E3Q]kB1 variants (Table 2, Fig. 3 and 4). The plug and play approach futher allowed to successfully graft dynA in loop 3 (11.2% yield) and loop 5 (7.1% yield). Also ∆L3[E3Q]kB1-dynA and ∆L5[E3Q]kB1-dynA were assessed in binding and functional activity assays and were found to exhibit nanomolar affinities at KOR with full agonist activity (Table 1). Example 11: β-arrestin recruitment-based BRET assay - β-arrestin recruitment profile The ability of the cyclotide-dynorphin grafts to induce β-arrestin recruitment at a ligand concentration of 1 µM at KOR was investigated. U50,488 was used as a positive control. To explore β-arrestin recruitment, the BRET assay was utilized by tagging β-arrestin with the fluorescence donor nLuc and tagging mouse KOR with the fluorescence acceptor green fluorescent protein (GFP). Receptor activation can lead to the ligand-dependent recruitment of β-arrestin-nLuc to mKOR-GFP resulting in increased BRET ratio (Donthamsetti, Curr Protoc Pharmacol. 2015; https: / / doi.org / 10.1002 / 0471141755.ph0214s70). To measure β-arrestin recruitment, HEK293 cells were seeded into 6-well plates in DMEM with L-glutamine and phenol red supplemented with FBS and P / S and transiently transfected at approximately 70% confluence. The transfection mixture contained 1800 ng of a mKOR-GFP-plasmid, 200 ng of a β- arrestin-nano-luciferase-plasmid and 4 µl of jetPRIME transfection reagent in 200 µl of transfection buffer. Cell transfection was performed according to the manufacturer’s protocol (Polyplus). The transfected cells were subsequently incubated at 37°C and 5% CO2 for 4-6 h. Afterwards the cells were transferred into white clear-bottom cell culture 96-well plates in 100 µl of phenol red-free DMEM supplemented with 10% FBS and P / S at a density of 50^000 cells / 100 μL / well. The cells were incubated overnight at 37 °C and 5% CO2to ensure adherence to the plate bottom. On the following day, the cells were serum starved for 1 h at 37 °C and 5% CO2 by switching the medium to phenol red-free DMEM without any supplements. The nano- luciferase substrate furimazine was prepared at 1:50 dilution in HBSS, and ligand concentrations were also prepared in HBSS. Prior to measurement, 50 µl of diluted furimazine was added to each well containing the cells, and the cells were incubated for 5 min at 37 °C. After those 5 minutes, 50 µL of ligand solution were added to each well. BRET measurements were then taken over 20 min, and emissions were sequentially measured at 460 nm for Nluc and 510 nm for GFP. Ligand-induced β-arrestin recruitment could then be seen as an increase in BRET ratio. In total, each well contained 100 µl DMEM with HEK293 cells, 50 μl 1:50 diluted furimazine, and 50 μl ligand solution. For single-concentration measurements, the ligand concentrations were 4 µM to achieve a final concentration of 1 µM. For concentration-response measurements, a semi logarithmic dilution series of ligand concentrations has been prepared. Single-concentration measurements were performed in technical duplicates, concentration-response measurements were performed in technical triplicates. The results of the BRET-based β-arrestin recruitment assays are as follows. The ligands KB1- dynA(L3) (∆L3[E3Q]kB1-dynA; SEQ ID NO: 3) and KB1-dynA(L6) (∆L6[E3Q]kB1-dynA (SEQ ID NO: 5) both displayed the ability to induce the recruitment of β-arrestin 2 and showed notably higher β-arrestin 1 recruitment compared to the reference ligand. Opposed to that, KB1- dynA(L5) (∆L5[E3Q]kB1-dynA; SEQ ID NO: 4) only induced modest β-arrestin 1 recruitment and no recruitment of β-arrestin 2. Table 6 illustrates the ligand-dependent β-arrestin recruitment at KOR induced by the cyclotide- dynorphin grafts. The data derived from the BRET-based assays has been calculated and normalized (100%) to the reference compound U50,488 as described above. At the examined concentration, both ligands KB1-dynA(L3) and KB1-dynA(L6) recruited more β-arrestin 1 than U50,488, with respective efficacy values of 124% and 143%. Additionally, both ligands recruited β-arrestin 2 with similar efficacy to U50,488, with values of 110% and 102%, respectively. KB1- dynA(L5) demonstrated modest β-arrestin 1 recruitment, with an efficacy value of 25% compared to U50,488. The negative values for β-arrestin 2 recruitment suggest no recruitment to the receptor. For example, it can be seen that kB1-dynA(L6) induced β-arrestin recruitment (at single concentration of 1 µM), whereas the other test ligands only activated different G protein isoforms to varying degrees (Example 12, below) without inducing β-arrestin recruitment. Example 12: G protein dissociation-based BRET assay - G protein activation profile The ability of the cyclotide-dynorphin grafts to induce G protein dissociation across different G protein isoforms was investigated at a single concentration of 1 µM, using U50,488 as a reference ligand. The G protein activation at KOR was measured by utilizing BRET assays in a different manner compared to the β-arrestin recruitment-based BRET assay mentioned above. Heterotrimeric G proteins, consisting of the Gα, Gβ, and Gγ subunit, are membrane-anchored complexes and represent the most important transducer proteins of GPCRs. In inactive receptor state, the three subunits form a holoenzyme with guanosine diphosphate (GDP). GPCR activation following agonist binding leads to the exchange of GDP for guanosine triphosphate (GTP) resulting in G protein dissociation and formation of active Gα and Gβγ proteins leading to a variety of cellular mechanism. In contrast to the β-arrestin recruitment-based BRET assay, the Gα and Gβγ subunit have been linked with the donor protein nano-Luciferase (nLuc) and the fluorescence acceptor cpVenus, respectively. Ligand-induced GPCR activation and subsequent G protein dissociation leads to a distance between the tagged Gα and Gβγ subunits and thereby a decrease in BRET ratio (Schihada, Sci Signal.2021; https: / / doi.org / 10.1126 / scisignal.abf1653). To measure the G protein activation and thereby the G protein dissociation, HEK293 cells stably expressing the murine KOR were seeded into 6-well plates in DMEM with L-glutamine and phenol red supplemented with FBS and P / S and transiently transfected at approximately 70% confluence. The transfection mixture contained 2000 ng of a Gα-nLuc and Gβγ-cpVenus tagged G protein plasmid together with 4 µl of jetPRIME transfection reagent in 200 µl of transfection buffer. Cell transfection was performed according to the manufacturer’s protocol (Polyplus). The following steps were performed as described above: The transfected cells were subsequently incubated at 37°C and 5% CO2 for 4-6 h, transferred into white clear-bottom cell culture 96-well plates in 100 µl of phenol red-free DMEM supplemented with 10% FBS and P / S at a density of 50^000 cells / 100 μL / well and incubated overnight at 37 °C and 5%.1 h prior to the measurement, the cells were serum starved by switching the medium to phenol red-free DMEM without any supplements and incubated 37 °C and 5% CO2. Ligand concentrations and 1:50 diluted furimazin were prepared in HBSS. Subsequently, 50 µL of diluted furimazine was added to each well containing the cells, and the cells were incubated for 5 min at 37 °C before starting the measurements. After those 5 minutes, 50 µL of ligand solution were added to each well. BRET measurements were then taken over 20 min, and emissions were sequentially measured at 460 nm for Nluc and 530 nm for cpVenus. Ligand-induced G protein dissociation was presented as a decrease in BRET ration, in contrast to β-arrestin recruitment mentioned above. In total, each well contained 100 µl DMEM with HEK293 cells stably expressing mKOR, 50 μl 1:50 diluted furimazine, and 50 μl ligand solution. For single-concentration measurements, the ligand concentrations were 4 µM to achieve a final concentration of 1 µM. Single-concentration measurements were performed in technical duplicates, concentration- response measurements were performed in technical triplicates. The results of these experiments were as follows. The examined ligands caused G protein dissociation to varying extents in all tested G protein isoforms except for Gαs, which is a stimulatory G protein isoform and does not induce signaling pathways at KOR. The two peptide ligands KB1-dynA(L3) (∆L3[E3Q]kB1-dynA; SEQ ID NO: 3) and KB1-dynA(L6) (∆L6[E3Q]kB1-dynA (SEQ ID NO: 5) exhibited a similar G protein activation profile, activating every tested G protein isoform with similar efficacy, and their G protein activation potential, as shown in BRET ratio, was comparable to that of the reference compound U50,488 except at Gαi1, where both ligands displayed slightly lower G protein activation. In contrast, at the tested concentration, KB1- dynA(L5) (∆L5[E3Q]kB1-dynA; SEQ ID NO: 4) displayed notably lower efficacy in activating Gαi1- 3 and Gαo1 than the reference agonist U50,488. All ligands exhibited similar efficacy in activating Gαq, Gα13 and Gα15. Table 5 illustrates the ligand-dependent activation of G protein isoforms induced by U50,488 and cyclotide-dynorphin grafts at 1 µM ligand concentrations The data derived from the BRET- based assays has been normalized (100%) to the BRET ratio elicited by the unbiased reference compound U50,488. The respective values for each ligand were computed by calculating the mean value of the corresponding BRET ratio amplitude, with the baseline already subtracted, from 540 seconds to 1500 seconds, which marks the end of the measurement. The selection of the 540-second time point corresponds to when the ligands initially exhibit their maximum response in BRET ratio at KOR. The peptide ligands KB1-dynA(L3) and KB1-dynA(L6) displayed similar efficacy in activating the investigated G proteins. Both ligands were able to induce G protein isoform activation at Gαi2-3, Gαo1, and Gαq with comparable efficacy to the reference ligand U50,488, ranging from 98% to 119%. Both ligands showed higher efficacy in activating Gα15, with respective efficacies of 132% and 113%. In addition, KB1-dynA(L3) and KB1-dynA(L6) exhibited a slightly lower ability to activate Gαi1 compared to U50,488, with efficacy values of 85% and 81%, respectively. At the tested concentration of 1 µM ligand concentration, KB1- dynA(L5) demonstrated a lower ability to activate the investigated G protein isoforms, with efficacy values ranging from 57% to 79% compared to U50,488. Example 13: Data analysis (in particular concerning Examples 11 and 12) Data analysis was performed using GraphPad Prism (GraphPad Software, San Diego). To calculate the respective ligands efficacy at KOR in activating the different G protein isoforms and to recruit β-arrestins, the data derived from the single-concentration BRET-based assays has been normalized (100%) to the BRET ratio elicited by the unbiased reference compound U50,488. The respective values for each ligand were computed by calculating the mean value of the corresponding BRET ratio amplitude, with the baseline already subtracted, from 540 seconds to 1500 seconds, which marks the end of the measurement. The selection of the 540- second time point corresponds to when the ligands initially exhibit their maximum response in BRET ratio at KOR. Concentration-response curves of BRET assays were fitted to three- parameter non-linear regression models and subsequently normalized to the BRET ratio of the reference compound U50,488 set as 100%. Bias factors were calculated using the formula according to Kolb et al.: Bias factor = 10ΔΔlog(Tau / Ka). Δlog(Tau / Ka) is calculated as log(Tau / Ka)ligand - log(Tau / Ka)reference. To calculate the bias for a specific pathway compared to another (ΔΔlog(Tau / Ka), the Δlog(Tau / Ka) of the pathway with less activation must be subtracted from the Δlog(Tau / Ka) of the pathway with the stronger activation. The Bias factor ( 10ΔΔlog(Tau / Ka)) is the antilog of the ΔΔlog(Tau / Ka) value (Kolb, Community guidelines for GPCR ligand bias: IUPHAR review 32. Br J Pharmacol.2022; https: / / doi.org / 10.1111 / bph.15811). Data obtained from radioligand displacement binding assays were normalized to the specific binding of [3H]- diprenorphine in the absence of competing ligands as the 100% reference point. Reference is made herein to the following table(s): Table 1: Pharmacological data of [E3Q]kB1-dynA grafts at the κ-opioid receptor peptide Ki (nM) EC50 (nM) Emax (%) Dynorphin A 1-13 n.d. 3.4 ± 0.9 100 ∆L6[E3Q]kB1-dynA 6.2 ± 4.2 68.8 ± 23.1 139.4 ± 20.2 ∆L3[E3Q]kB1-dynA 1.4 ± 0.9 28.0 ± 9.8 109.0 ± 27.4 ∆L5[E3Q]kB1-dynA 3.2 ± 1.7 112.3 ± 68.2 128.0 ± 21.0 Data are mean ± SD from n=3 Table 2: Linear oxidized scaffold peptides Peptide SequenceaMass (Da)byield (%)c Table 3: Linear protected epitopes Peptide SequenceaMass (Da)byield (%)ccalculated observed Boc-L6 Boc-R(Pbf)N(Trt)GLP11150.3 [M+H]+1150.5 [M+H]+50.9 Boc-dynA Boc-Y(tBu)GGFLR(Pbf)R(Pbf)IR(Pbf)PK(ivDde)LK(ivDde)21465.0 [M+2H]+2, 977.0 1465.4 [M+2H]+2, 977.2 n.d.d[M+3H]+3[M+3H]+3aAll peptides were synthesized as C-terminal acids;bRepresents monoisotopic mass of oxidized peptides;cYields were calculated based on initial resin loading:dn.d. not determined;1SEQ ID NO: 56,2SEQ ID NO: 57 Table 4: Plug and play grafted peptides and cyclic controls Peptide SequenceaMass (Da)byield (%)ccalculated observed kB1 c-CGETCVGGTCNTPGCTCSWPVCTRNGLPV11446.1 [M+2H]+21446.5 [M+2H]+2n.d.d[E3Q]kB1 c-CGQTCVGGTCNTPGCTCSWPVCTRNGLPV21445.6 [M+2H]+21446.1 [M+2H]+223.5 / 26.1ekB1 p+p c-CGETCVGGTCNTPGCTCSWPVCTRNGLPV11446.1 [M+2H]+21446.6 [M+2H]+210.6 [E3Q]kB1 p+p c-CGQTCVGGTCNTPGCTCSWPVCTRNGLPV21445.6 [M+2H]+21446.0 [M+2H]+224.8 ∆L6[E3Q]kB1-dynA c-YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT31313.3 [M+3H]+3, 985.2 1313.5 [M+3H]+3, 985.5 17.455[M+4H]+4, 788.4 [M+5H]+5[M+4H]+4, 788.5 [M+5H]+5∆L3[E3Q]kB1-dynA c-YGGFLRRIRPKLKGCTCSWPVCTRNGLPVCGQTCVGGTCN41426.4 [M+3H]+3, 1070.0 1426.5 [M+3H]+3, 1070.3 11.2 [M+4H]+4, 856.2 [M+5H]+5[M+4H]+4, 856.3 [M+5H]+5∆L5[E3Q]kB1-dynA c-YGGFLRRIRPKLKVCTRNGLPVCGQTCVGGTCNTPGCTCS51398.0 [M+3H]+3, 1048.8 1398.2 [M+3H]+3, 1048.9 7.1 [M+4H]+4, 839.2 [M+5H]+5[M+4H]+4, 839.3 [M+5H]+5ac denotes backbone cyclization, all cysteines are oxidized;bRepresents monoisotopic mass of fully oxidized peptides;cYields were calculated based on initial amount of starting material used for ligation;dn.d. not determined – authentic control material obtained from previous work1;eYields represent oxidation yields for initial and optimized conditions and are calculated by automated integration of the area under the curve;1SEQ ID NO: 1,2SEQ ID NO: 2,3SEQ ID NO: 5,4SEQ ID NO: 3,5SEQ ID NO: 4

[0002] 2 Table 5: Efficacy values [%] for ligand-dependent G protein activation induced by addition of 1 µM kB1-dynA grafts. All experiments were performed in two independent measurements (n=2). The obtained BRET ratio after addition of 1 µM U50,488 was used for normalization (100%) and calculated as described herein elsewhere. Gαi1 Gαi2 Gαi3 Gαo1 Gαq Gα13 Gα15 kB1- 84.8 ± 119.7 ± 46.6 ± 132.1 ± dynA(L3)13.4 106.3 ± 7.2 100.8 ±8.6 98.5 ± 0.2 24.0 14.7 2.5 kB1- dynA(L5)256.8 ± 0.4 79.4 ± 0.4 59.2 ±12.8 68.6 ± 1.4 74.8 ± 10.6 75.8 ± 9.8 74.9 ± 0.3 kB1- 81.2 ± 0.5 108.4 ± 1.6 98.1 110.5 ± 113.1 ± 112.6 ± dynA(L6)3±2.7 97.7 ± 1.8 22.8 33.6 1.0 60- 20- 10- ≥90% 89% 59% 19% Ranges of G protein activation1∆L3[E3Q]kB1-dynA (SEQ ID NO: 3),2∆L5[E3Q]kB1-dynA (SEQ ID NO: 4),3∆L6[E3Q]kB1-dynA (SEQ ID NO: 5)56Table 6: Efficacy values [%] for ligand-dependent β-arrestin recruitment induced by addition of kB1-dynA grafts at 1 µM ligand concentrations at KOR. The experiment was performed in three independent measurements (n=3) for β-arrestin 1 and in two independent measurements (n=2) for β-arrestin 2 recruitment. For efficacy value calculations, the obtained BRET ratio after addition of 1 µM U50,488 was used for normalization (100%) as described elsewhere. β-arrestin 1 β-arrestin 2 kB1-dynA(L3)1124.3 ± 15.1 110.2 ± 24.8 kB1-dynA(L5)225.1 ± 4.5 -34.3 ± 34.7kB1-dynA(L6)3142.8 ± 23.5 101.8 ± 24.5 ≥90% 60-89% 20-59% 10-19% 1-9% ≤0% Ranges of β-arrestin recruitment1∆L3[E3Q]kB1-dynA (SEQ ID NO: 3),2∆L5[E3Q]kB1-dynA (SEQ ID NO: 4),3∆L6[E3Q]kB1-dynA (SEQ ID NO: 5)

Claims

New PCT Patent Application Medizinische Universität Wien; The University of Queensland Vossius Ref.: AJ1533 PCT S3 1 CLAIMS 1. A grafted cyclotide comprising (I) a cyclic cystine knot (CCK) derived from kalata B1 (kB1; SEQ ID NO: 1); and (II) an amino acid sequence derived from dynorphin A (dynA sequence), wherein said dynA sequence is comprised in (i) the inter-cysteine loop 3 of said CCK (loop 3); (ii) the inter-cysteine loop 5 of said CCK (loop 5); or (iii) the inter-cysteine loop 6 of said CCK (loop 6), and wherein the inter-cysteine loop 1 of said CCK (loop 1) comprises a mutation which corresponds to the mutation Glu3Gln (E3Q) in SEQ ID NO:

2.

2. The grafted cyclotide according to claim 1, wherein the inter-cysteine loop 4 of said CCK (loop 4) comprises or consists of a Thr residue (T).

3. The grafted cyclotide according to claim 1 or 2, wherein said dynA sequence consists of (or comprises) an amino acid sequence selected from the group consisting of: (i) YGGFLRRIRPKLK (SEQ ID NO: 36; most preferred). (ii) YGGFLRRI (SEQ ID NO: 37; preferred); (iii) YGGFLRRIR (SEQ ID NO: 38; preferred); (iv) YGGFLRRIRP (SEQ ID NO: 39); (v) YGGFLRRIRPK (SEQ ID NO: 40; preferred); (vi) YGGFLRRIRPKL (SEQ ID NO: 41); (vii) any one of the amino acid sequences (i) to (vi) having 1, 2, 3 or 4 of Arg7, Ile8, Pro10 and Lys11 substituted by N(alpha)-metyl-Arg7 or D-Arg 7, D-Ile8 or Dap(2,3 diaminopropionic acid), D-Pro10 or Dap, and / or N(alpha)-metyl-Lys11 or D- Lys11, respectively.

4. The grafted cyclotide according to any one of claims 1 to 3, wherein said grafted cyclotide comprises an amino acid sequence selected from the group consisting of: (i) GCTCSWPVCTRNGLPVCGQTCVGGTCN (SEQ ID NO: 33); (ii) VCTRNGLPVCGQTCVGGTCNTPGCTCS (SEQ ID NO: 34); and (iii) VCGQTCVGGTCNTPGCTCSWPVCT (SEQ ID NO: 35).2 5. The grafted cyclotide according to any one of claims 1 to 4, which is a grafted cyclotide selected from the group consisting of: (i) cyclo-YGGFLRRIRPKLKGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA; SEQ ID NO: 3; SEQ ID NO: 9; ∆L3[E3Q]kB1-dynA3.4); (ii) cyclo-YGGFLRRIRPKLKVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA; SEQ ID NO: 4; SEQ ID NO: 13; ∆L5[E3Q]kB1-dynA2.4); (iii) cyclo-YGGFLRRIRPKLKVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA; SEQ ID NO: 5; SEQ ID NO: 17; ∆L6[E3Q]kB1-dynA1.4); (iv) cyclo-YGGFLRRIRPKGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.1; SEQ ID NO: 6); (v) cyclo-YGGFLRRIRGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.2; SEQ ID NO: 7); (vi) cyclo-YGGFLRRIGCTCSWPVCTRNGLPVCGQTCVGGTCN (^L3[E3Q]kB1-dynA3.3; SEQ ID NO: 8; (vii) cyclo-YGGFLRRIRPKVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.1; SEQ ID NO: 10); (viii) cyclo-YGGFLRRIRVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.2; SEQ ID NO: 11); (ix) cyclo-YGGFLRRIVCTRNGLPVCGQTCVGGTCNTPGCTCS (^L5[E3Q]kB1-dynA2.3; SEQ ID NO: 12); (x) cyclo-YGGFLRRIRPKVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.1; SEQ ID NO: 14); (xi) cyclo-YGGFLRRIRVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.2; SEQ ID NO: 15); and (xii) cyclo-YGGFLRRIVCGQTCVGGTCNTPGCTCSWPVCT (^L6[E3Q]kB1-dynA1.3; SEQ ID NO: 16).

6. The grafted cyclotide according to claim 4 or 5, wherein said amino acid sequence or cyclotide has 1, 2, 3 or 4 of the the amino acid substitution(s) as defined in claim 3(vii).

7. The grafted cyclotide according to any one of claims 1 to 6, wherein said grafted cyclotide (a) is a KOR agonist which activates the kappa opioid receptor (KOR) with an ECmax in the range of 80-170% (as compared to Dynorphin A 1-13 (100%)) and / or with a potency / efficacy in the range of 10 nM to 130 nM, wherein activation and potency / efficacy are determined by a functional cAMP inhibition assay; and / or3 (b) binds to KOR at an affinity corresponding to a Ki in the range of 0.5 nM to 10 nM, wherein the affinity is determined by a radioligand competition binding assay.

8. The grafted cyclotide according to claim 7, wherein wherein said grafted cyclotide (a) is a KOR agonist which activates the kappa opioid receptor (KOR) with an ECmax in the range of 100-150% (as compared to Dynorphin A 1-13 (100%)) and / or with a potency / efficacy in the range of 20 nM to 120 nM, wherein activation and potency / efficacy are determined by a functional cAMP inhibition assay; and / or (b) binds to KOR at an affinity corresponding to a Ki in the range of 1.0 nM to 7 nM, wherein the affinity is determined by a radioligand competition binding assay.

9. A pharmaceutical composition comprising the grafted cyclotide according to any one of claims 1 to 8, and optionally a pharmaceutically acceptable carrier.

10. A pharmaceutical composition comprising the grafted cyclotide according to any one of claims 1 to 8, and optionally a pharmaceutical carrier, for use in (i) treating inflammation; and / or (ii) treating pain, diarrhea, rectal bleeding, fatigue and / or weight loss; and / or (iii) treating itching and / or disorders associated with itching.

11. The pharmaceutical composition for use according to claim 10, wherein (i) said inflammation is peripheral inflammation; and / or (ii) said pain is chronic and / or peripheral pain.

12. The pharmaceutical composition for use according to claim 10 or 11, wherein (i) said inflammation is inflammatory bowel disease (IBD); and / or (ii) said pain is abdominal pain, visceral pain, peripheral neuropathic pain; and / or 13. The pharmaceutical composition for use according to any one of claims 10 to 12, wherein (i) said inflammation is ulcerative colitis or Crohn's disease; and / or (ii) said pain, diarrhea, rectal bleeding, fatigue and / or weight loss is pain diarrhea, rectal bleeding, fatigue and / or weight loss relating to / coming along with (i).

14. The pharmaceutical composition according to claim 9 or the pharmaceutical composition for use according to any one of claims 10 to 13, wherein said grafted4 cyclotide or said pharmaceutical composition is (to be) administered perorally (e.g. in form of tablets; pills; capsules; powders; solutions; suspensions).

15. The pharmaceutical composition according to claim 14 or the pharmaceutical composition for use according to claim 14, wherein said grafted cyclotide or said pharmaceutical composition is (to be) administered in form of tablets; pills; capsules; powders; solutions; suspensions.

16. A method of preparing a kB1-derived grafted cyclotide comprising a CCK derived from kB1, said method comprising the following steps (i) preparing / providing a peptide backbone derived from kB1 in form of a linear peptide, wherein said peptide backbone comprises the six conserved Cys residues (CI-VI) of kB1; (ii) allowing said six conserved C residues to form three disulfide-bridges so as to form a cystine knot (CK) motif, thereby forming an (acyclic but folded) grafting scaffold; (iii) preparing / providing a dynA sequence in form of a linear peptide; (iv) allowing said grafting scaffold of (ii) to assemble / ligate with said dynA sequence of (iii), so as to cyclize said grafting scaffold with said dynA sequence to form said grafted cyclotide (including the formation of the CCK motif), wherein step (ii) is performed prior to step (iv).

17. The method according to claim 16, said method further comprising the following step (iii´) protecting said dynA sequence.

18. The method according to claim 16 or 17, wherein step (iii´) is a step of protecting the N- terminus and the side-chains in need of protection of said dynA sequence.

19. The method according to any one of claims 16 to 18, wherein step (iii´) is a step of protecting any comprised lysine (K) residue(s), any comprised tyrosine (Y) residue(s), and / or any comprised arginine (R) residue(s).

20. The method according to any one of claims 16 to 19, wherein step (iii´) is a step of protecting any comprised lysine (K) residue(s) by ivDde protection, any comprised tyrosine (Y) residue(s) by tBu protection, and / or any comprised arginine (R) residue(s) by Pbf protection.5 21. The method according to any one of claims 16 to 20, wherein in step (iv), (a) the N-terminus of said grafting scaffold is first ligated with the C-terminus of said dynA sequence with a protected N-terminus and with protected side-chains; (b) the ligated dynA sequence is deprotected; and (c) the C-terminus of said grafting scaffold is afterwards ligated with the deprotected N-terminus of said dynA sequence.

22. The method according to claim 21, wherein in step (iv), the N-terminus of said grafting scaffold is first ligated with the C-terminus of said dynA sequence with a protected N- terminus and with protected side-chains as defined in any one of claims 17 to 20.

23. The method according to any one of claims 16 to 22, wherein said peptide backbone and / or grafting scaffold comprises a kB1-derived amino acid sequence as defined in any one of claims 1, 2, 4 or 5, wherein said grafted cyclotide is defined as in any one of claims 1 to 8, and / or wherein said dynA sequence is defined as in any one of claims 1, 5 and 6.

24. A grafting scaffold comprising a CK motif as defined in any one of claims 1, 2, 4 and 5, a peptide backbone as comprised in a grafting scaffold comprising a CK motif as defined in any one of claims 1, 2, 4 or 5, a grafting scaffold as obtained by steps (i) and (ii) of the method of any one of claim 16 to 23, or a grafted cyclotide as obtained by the method of any one of claim 16 to 23.

Images