Derivative antibacterial peptide based on Tritrpticin as well as synthesis method and application thereof in antibacterial aspect

Abstract

The invention belongs to the technical field of medicines, and particularly relates to design, preparation and application of an antibacterial peptide derivative. According to the invention, Tritrpticin antibacterial peptide is taken as a structural template, and a series of polypeptide derivatives with symmetrical tail ends and beta-corner structures are designed and prepared. The polypeptide derivative disclosed by the invention has relatively high antibacterial activity and safety, and has a good application prospect in the antibacterial aspect.

Description

Technical Field

[0001] The present invention belongs to the field of medical technology, and specifically relates to a derivative antimicrobial peptide based on Tritrpticin, a synthesis method thereof, and an application thereof in antibacterial aspects. Background Art

[0002] At present, the abuse of antibiotics has become a global public health problem. It accelerates the emergence of multidrug-resistant bacteria and poses a serious threat to human health. The development of alternative antibiotics that are less likely to cause bacterial resistance is particularly critical in curbing drug-resistant bacterial infections. Antimicrobial peptides, as a class of bioactive molecules widely present in nature, generally exhibit broad-spectrum antimicrobial activity. To date, more than 10,000 natural antimicrobial peptides have been identified, which exhibit a variety of conformations including α-helix, β-fold and random coil. These natural antimicrobial peptides mainly exert their antibacterial effects through non-specific membrane-destructive mechanisms. This antibacterial mechanism is fast and does not require receptor mediation. It is lethal to bacteria and is not likely to cause bacterial resistance. Natural antimicrobial peptides are usually composed of cationic residues and hydrophobic residues. Their positive charge and amphipathicity are crucial to their membrane-destructive effects.

[0003] Tritrpticin (VRRFPWWWPFLRR) is a natural antimicrobial peptide with broad-spectrum antimicrobial activity. It consists of a β-turn structure (FPWWWPF) in the middle and two terminal extension chains rich in cationic and hydrophobic residues (VRRF, FLRR). It inhibits bacterial growth or kills bacteria mainly through membrane destruction mechanism. Among them, the three consecutive tryptophan residues (WWW) in the β-turn structure can be anchored on the bacterial cell membrane through the indole ring side chain, thereby enhancing the interaction between the peptide and the bacterial cell membrane; the cationic and hydrophobic residues in the two terminal extension chains can promote the adsorption and insertion of the peptide into the bacterial cell membrane through electrostatic interaction and hydrophobic interaction, respectively. The unique structure of tritrpticin provides an ideal template for the design of antimicrobial peptides. Antimicrobial peptides based on the combination of β-turn structure fragments and terminal symmetrical amphiphilic structure fragments show good application prospects in antibiotic substitution. Summary of the invention

[0004] The present invention provides a class of derivative antimicrobial peptides based on Tritrpticin, wherein the antimicrobial peptide has an amino acid sequence as shown in the general formula (1) or (2):

[0005] X(YX) n ZZ(XY) n X(1)

[0006] (YX) n ZZ(XY) n (2)

[0007] According to an embodiment of the present invention, n is selected from 1, 2, 3;

[0008] According to an embodiment of the present invention, ZZ is selected from the β-turn sequence FPWWWPF or PWWWP;

[0009] According to an embodiment of the present invention, each X is the same or different and is independently selected from a basic amino acid or an amino acid derivative with a positive charge on the side chain, for example, it can be selected from lysine (Lys, K), arginine (Arg, R), and one of other amino acid derivatives with a positive charge on the side chain, such as ornithine (Orn, O), homoarginine (Har);

[0010] According to an embodiment of the present invention, each Y is the same or different and is independently selected from a hydrophobic amino acid or a hydrophobic amino acid derivative, for example, it can be selected from tryptophan (Trp, W), tyrosine (Tyr, Y), phenylalanine (Phe, F), leucine (Leu, L), isoleucine (Ile, I), valine (Val, V), alanine (Ala, A), and one of other hydrophobic amino acid derivatives, such as naphthylalanine (Nal).

[0011] According to an embodiment of the present invention, the amino acid or amino acid derivative is in L-form or D-form.

[0012] According to an embodiment of the present invention, the N-terminal group of the antimicrobial peptide is a free amino group or is acetylated; for example, the N-terminal group is an acetylamino group.

[0013] According to an embodiment of the present invention, the C-terminal group of the antimicrobial peptide is a carboxyl group or is amidated; for example, the C-terminal group is amidated to become an amide group.

[0014] According to a preferred embodiment of the present invention, the antimicrobial peptide has an amino acid sequence as shown below:

[0015] SEQ ID NO.1(FP-11):KVKVKFPWWWPFKVKVK-NH2

[0016] SEQ ID NO.2(P-07):KIKIKPWWWPKIKIK-NH2

[0017] According to a preferred embodiment of the present invention, the antimicrobial peptide is composed of L-type amino acids, the N-terminal group of the antimicrobial peptide is acetylated, and / or the C-terminal is amidated.

[0018] According to a preferred embodiment of the present invention, the key physicochemical properties of the antimicrobial peptides FP-11 and P-07 are shown in Table 1:

[0019] Table 1 Key physical and chemical properties of FP-11 and P-07

[0020]

[0021] According to an embodiment of the present invention, the antimicrobial peptide is synthesized by solid phase synthesis.

[0022] The present invention also provides an antibacterial drug, which comprises a therapeutically effective amount of the antibacterial peptide.

[0023] The present invention also provides the use of the antimicrobial peptide in the preparation of antimicrobial drugs.

[0024] According to an embodiment of the present invention, the antibacterial drug is used to treat an infection (e.g., skin wound infection) caused by a pathogen. According to an embodiment of the present invention, the pathogen is selected from Gram-positive bacteria or Gram-negative bacteria, for example, selected from Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella aerogenes, Streptococcus, Bacillus or at least one of its multi-drug resistant strains. Preferably, it is a drug-resistant Escherichia coli.

[0025] The present invention also provides a combined antibacterial drug, the active ingredients of which include a therapeutically effective amount of the antibacterial peptide and an antibacterial antibiotic.

[0026] According to an embodiment of the present invention, the combined antimicrobial drug is used to treat infection caused by pathogens (eg, skin wound infection). According to an embodiment of the present invention, the antimicrobial peptide is preferably antimicrobial peptide P-07.

[0027] According to an embodiment of the present invention, the antibiotic is selected from at least one of polypeptide antibiotics, penicillin antibiotics, β-lactam antibiotics, quinolone antibiotics, cephalosporin antibiotics, and semi-synthetic carbapenem antibiotics. Preferably, the antibiotic is levofloxacin, a quinolone antibiotic.

[0028] According to an embodiment of the present invention, the pathogen is selected from Gram-positive bacteria or Gram-negative bacteria, for example, selected from at least one of Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella aerogenes, Streptococcus, Bacillus or multi-drug resistant strains thereof. Preferably, it is drug-resistant Escherichia coli.

[0029] Beneficial Effects

[0030] The derivative antimicrobial peptide based on Tritrpticin of the present invention is composed of a β-turn structure and a terminal symmetrical hydrophilic-hydrophobic alternating amino acid sequence, has a good structural basis for exerting antibacterial effects, shows strong anti-resistant bacteria activity and high safety, for example, it shows broad-spectrum antibacterial activity against multi-drug resistant strains of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii, and has a low hemolysis rate and HEK-293T cytotoxicity. As an antibiotic synergistic adjuvant, the antimicrobial peptide can be used in combination with the antibiotic levofloxacin to effectively treat skin wound infections caused by drug-resistant Escherichia coli. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the HPLC chromatogram of the antimicrobial peptide FP-11;

[0032] Figure 2 is the high performance liquid chromatogram of the antimicrobial peptide P-07;

[0033] Figure 3 is the mass spectrum of antimicrobial peptide FP-11;

[0034] Figure 4 is the mass spectrum of antimicrobial peptide P-07;

[0035] Figure 5 The hemolytic properties of Tritrpticin and its derivatives (FP-11, P-07);

[0036] Figure 6 The cytotoxicity of Tritrpticin and its derivatives (FP-11, P-07) on HEK-293T cells;

[0037] Figure 7The effect of antimicrobial peptide P-07 combined with antibiotic levofloxacin on promoting wound healing in mice; (A) Schematic diagram of wound infection development and treatment procedures; Bacterial load of E. coli ATCC 25922 (B) and resistant E. coli (C) in mouse skin wounds three days after administration; (D) Agar plate colony count of E. coli ATCC 25922 and resistant E. coli in mouse skin wounds three days after administration; (E) Weight changes of mice infected with resistant E. coli during administration; (F) Representative photos of mouse skin wounds infected with resistant E. coli within 11 days (scale bar: 5 mm); (G) Changes in wound size of mice infected with resistant E. coli during administration; (H) H&E and interleukin-6 (IL-6) analysis of wound tissues of infected mice on day 11 after administration (scale bar: 100 μm). The red box indicates the epidermis of different groups. The black arrow indicates the loss and damage of the epidermis. The yellow arrow indicates inflammatory cell infiltration. Red arrows indicate vascular congestion and dilation. Green arrows indicate tissue bleeding. Un-inf is the negative control group; NS is the normal saline group; Normal is the blank control group; L is the levofloxacin group. One-way analysis of variance (ANOVA) and T-test were used to analyze whether there were significant differences between the data (p<0.05: *, p<0.01: **, p<0.001: ***). DETAILED DESCRIPTION

[0038] The technical solution of the present disclosure will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary illustrations and explanations of the present disclosure and should not be construed as limiting the scope of protection of the present disclosure. All technologies implemented based on the above content of the present disclosure are included in the scope of protection intended by the present disclosure.

[0039] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0040] Example 1

[0041] Synthesis, identification and purification of antimicrobial peptides:

[0042] 1. Solid phase synthesis of peptides (FP-11 and P-07):

[0043] ① The reaction was carried out at room temperature, with a reaction scale of 0.25 mmol, using Rink Amide-AM resin (loading capacity of 0.53 mmol / g) as the starting point for synthesis, and extending the peptide chain from the C-terminus to the N-terminus.

[0044] ② Add the resin into the reactor, add 10 mL of dichloromethane (DCM) to swell for 30 minutes, drain the solvent, wash with N,N-dimethylformamide (DMF) and DCM three times each, stir for 3 minutes each time, and drain the solvent.

[0045] ③ Add 5 mL of 20% piperidine / DMF (v / v), stir for 5 min, drain, then add an equal amount of deprotection reagent, stir for 20 min, drain, wash with DMF and DCM three times each, stir for 3 min each time, and drain.

[0046] ④ Take 4 equivalents of Fmoc-protected amino acid, O-benzotriazole-tetramethyluronium hexafluorophosphate (HBTU), 1-hydroxybenzotriazole (HOBT) and 8 equivalents of N, N-diisopropylethylamine (DIEA) and add them to 5 mL DMF, activate for 10 minutes, then add them together to the reactor and stir, react for 1 hour, drain, wash with DMF and DCM 3 times, stir for 3 minutes each time, and drain.

[0047] ⑤ Repeat steps ③④ to connect the amino acids to the peptide chain one by one in order, wash with DMF and DCM 3 times each, stir for 3 minutes each time, and drain, and finally remove the N-terminal Fmoc protecting group, wash with DMF and DCM 3 times each, stir for 3 minutes each time, and drain.

[0048] 2. Detection of free amino groups:

[0049] Kaiser ninhydrin method is the most commonly used method to detect free amino groups. It can qualitatively detect whether the amide condensation reaction is complete through color reaction. The specific operation steps are as follows:

[0050] After each condensation reaction, clean the resin, take about 20 resin pellets, add 2-3 drops of ninhydrin indicator, and heat at 100℃ for 5 minutes. If the resin is colorless and transparent, it means that the reaction is complete and the next step can be carried out. If it is blue, it needs to be condensed again.

[0051] 3. Reagent preparation:

[0052] Ninhydrin indicator: Take 0.5g of ninhydrin powder and add 10mL of anhydrous ethanol, mix until completely dissolved.

[0053] Phenol solution: redistilled anhydrous phenol and anhydrous ethanol are mixed in a volume ratio of 4 / 1 to obtain a phenol solution.

[0054] Pyridine solution: pyridine solution after redistillation.

[0055] Cracking reagent: trifluoroacetic acid / triisopropylsilane / water = 90:5:5 (volume ratio)

[0056] 4. Lysis and freeze-drying:

[0057] After the peptide resin was prepared, 5 mL of anhydrous ether was added and stirred for 3 min. This was repeated 3 times. After the resin was fully dried, it was transferred to a 250 mL round-bottom flask, and a cleavage reagent (10 mL / mg) was added. The mixture was stirred for 30 min under ice bath conditions. After the ice bath was removed, the reaction was continued for 2.5 h. After the reaction was completed, anhydrous ether was added and stirred for 30 min. The mixture was allowed to settle and filtered to obtain the crude peptide.

[0058] Lyophilization: Collect the crude peptide solution and transfer it to a centrifuge tube, freeze it quickly under liquid nitrogen conditions, and obtain the crude peptide solid powder after lyophilization.

[0059] 5. Analysis and purification:

[0060] Analytical high performance liquid chromatography (HPLC) chromatographic conditions:

[0061] Chromatographic column: C18 column (250mm×4.6mm, 5μm)

[0062] Mobile phase A: 0.1% TFA / water, mobile phase B: 0.1% TFA / acetonitrile

[0063] Flow rate: 1mL / min; Detection wavelength: 210nm; Injection volume: 20μL

[0064] The elution procedure is shown in Table 2

[0065] The analysis was performed by analytical HPLC, the main peak tip was collected, and the molecular weight of the peptide was determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). After confirming that the molecular weight was consistent with the theoretical value, the peptide was purified.

[0066] Table 2 HPLC detection of crude peptide purity elution procedure

[0067]

[0068] 6. Peptide purification:

[0069] Weigh 50 mg of crude peptide, dissolve it in phase A to 50 mL, filter it through a 0.45 μm water-based microporous filter membrane, and then use it for preparative liquid chromatography separation and purification.

[0070] Preparative HPLC chromatographic conditions:

[0071] Chromatographic column: C18 preparative column (250mm×20mm, 5μm)

[0072] Mobile phase A: 0.1% TFA / water, mobile phase B: 0.1% TFA / acetonitrile

[0073] Flow rate: 15mL / min; Detection wavelength: 210nm; Injection volume: 5000μL

[0074] Adjust the purification elution procedure according to the physical and chemical properties of the target polypeptide, perform gradient elution at room temperature, collect the target polypeptide, and use analytical HPLC to detect the purity of the purified polypeptide. Collect the polypeptide solution with a purity greater than 95%, remove acetonitrile by rotary evaporator, collect the polypeptide aqueous solution and freeze-dry to obtain pure peptide solid, collect, weigh and seal in a centrifuge tube, and store at -40°C.

[0075] Example 2

[0076] Evaluation of in vitro antimicrobial activity of antimicrobial peptides:

[0077] The minimum inhibitory concentration (MIC) of tritrpticin and its derivative peptides in resistant strains of Enterococcus faecalis (E.faecalis), Staphylococcus epidermidis (S.epidermidis), Staphylococcus aureus (S.aureus), Escherichia coli (E.coli), Klebsiella pneumoniae (K.pneumoniae) and Acinetobacter baumannii (A.baumannii) was determined by the fold dilution method.

[0078] Place the strain at 37°C and shake at 150 rpm for overnight incubation. Transfer the bacterial suspension to a new medium until it grows to logarithmic growth and is ready for use. Determine the MIC of the peptide using the standard broth dilution method: dilute the bacterial suspension to 1×10 6 CFU / mL was used for standby, and the peptide solution was diluted 2 times with culture medium to 1-256μM. 50μL of bacterial suspension was mixed with an equal volume of peptide solution and added to a 96-well plate. The plate was incubated at 37°C constant temperature shaking incubator at 180r / min for 18h. After incubation, the bacterial growth in the 96-well transparent plate was observed. The minimum peptide concentration corresponding to the well with clear liquid was the MIC of the peptide. The experimental results are shown in Table 3. The modified antimicrobial peptides FP-11 and P-07 have good antibacterial activity against both Gram-positive and Gram-negative bacteria.

[0079] Table 3 MIC values ​​of Tritrpticin and its derivatives

[0080]

[0081] Example 3

[0082] Hemolytic test;

[0083] Human red blood cells were used to evaluate the hemolytic activity of antimicrobial peptides. Fresh red blood cells were washed three times with PBS and resuspended into a cell suspension (8%, v / v). The evenly dispersed cell suspension was quickly added to a sterile 96-well transparent plate, with 5 parallels for each concentration and 50 μL per well. Then 50 μL of polypeptide solution was added to each well. Untreated red blood cells were used as negative controls, and Triton-X100-treated red blood cells were used as positive controls. After the culture was completed, centrifuged at 1800 r / min for 5 minutes, and 50 μL of supernatant was aspirated from each well and added to a new 96-well transparent plate. The absorbance at 490 nm was measured by an enzyme-labeled instrument. The hemolysis rate was calculated as follows:

[0084] Hemolytic rate = [OD 490 nm(treatment) -OD 490 nm(negative control) ] / [OD 490 nm(positive control) -OD 490 nm(negative control) ]×100%.

[0085] OD 490 nm(treatment) : Indicates the absorbance value corresponding to the drug-dosing cell well

[0086] OD 490 nm(positive control) : Indicates the absorbance value corresponding to the positive control well

[0087] OD 490 nm(negative control) : Indicates the absorbance value corresponding to the negative control well

[0088] The experimental results are shown in Figure 5 , antimicrobial peptide FP-11 showed slight hemolysis within the detection range, while P-07 was not found to be hemolytic at the highest detection concentration.

[0089] Example 4

[0090] In vitro cell proliferation toxicity assay:

[0091] Human renal epithelial cells (HEK-293T) were used to evaluate the in vitro cytotoxicity of antimicrobial peptides. The cells were cultured to the logarithmic growth phase, and the evenly dispersed cell suspension was quickly added to a sterile 96-well plate, with 5 parallels for each concentration, 100 μL per well, and each well containing approximately 10,000 cells, and cultured at 37°C for 24 hours. After 24 hours, the original culture medium in the well plate was aspirated, and the prepared peptide solutions of each concentration were added to the culture plate. The negative control group was added with blank culture medium and no cells, and the positive control group was added with blank culture medium and the number of cells was consistent with that of the drug-treated group, and cultured at 37°C for 24 hours. At the end of the culture, the 96-well plate was removed, the original culture medium was aspirated, CCK-8 working solution was added, and the culture continued for 1 hour. The absorbance value at 450nm was measured by an enzyme reader, and the cell survival rate was calculated based on the value. The formula for calculating the cell survival rate is as follows:

[0092] Cell survival rate = [OD 450 nm(treatment) -OD 450 nm(negative control) ] / [OD 450nm(positive control) -OD 450 nm(negative control) ]×100%.

[0093] OD 450 nm(treatment) : Indicates the absorbance value corresponding to the drug-dosing cell well

[0094] OD 450 nm(positive control) : Indicates the absorbance value corresponding to the positive control well

[0095] OD 450 nm(negative control) : Indicates the absorbance value corresponding to the negative control well

[0096] The experimental results are shown in Figure 6 The antimicrobial peptides FP-11 and P-07 were less toxic to HEK-293T cells, and no cytotoxicity was detected within the effective inhibitory concentration range.

[0097] Example 5

[0098] In vivo wound healing assay

[0099] Male Kunming mice (6 weeks old, about 20 grams) were raised for 1 week to acclimate to the environment. Escherichia coli ATCC25922 and drug-resistant Escherichia coli were used to establish a full-thickness wound model of bacterial infection in mice. The mice were first anesthetized with sodium pentobarbital, and then the hair on the back of each mouse was shaved, and the exposed skin was disinfected with alcohol cotton balls. After that, a circular full-thickness wound with a diameter of about 8 mm was cut on the back of the mouse. The bacteria in the logarithmic growth phase were centrifuged, washed with PBS, and resuspended in PBS solution (1×10 5 CFU / mL). The bacterial suspension (100 μL per wound) was dripped onto the wound site. Biofilm appeared on the back wound of the mouse 24 hours after bacterial infection, indicating that the full-thickness wound model was constructed. The model mice were randomly divided into four groups, including saline group, P-07 group, levofloxacin group and P-07+levofloxacin group, with 5 mice in each group. In addition, 5 mice with wounds but not infected with bacteria and 5 normal mice were used as negative controls and blank controls, respectively. The drug concentration was set at 100 μM, and the antibacterial solution (50 μL) was dripped onto the wound once a day for 11 days. In order to record the process of wound healing, the wound was photographed daily and the wound size was measured with a caliper. On the 3rd day, the wound tissue of the mouse was homogenized and diluted with sterile saline, and then the bacteria were counted by flat plate coating method. On the 11th day, the skin tissue of the wound site was collected for hematoxylin and eosin (H&E) staining and immunohistochemical analysis.

[0100] The experimental results are shown in Figure 7 .like Figure 7 As shown in Figure B, P-07, levofloxacin, and P-07 combined with levofloxacin can significantly reduce the bacterial count of E. coli ATCC 25922 in the wound, and the bactericidal effects of levofloxacin and P-07 combined with levofloxacin are more significant than those of P-07. However, in the treatment of drug-resistant E. coli infection, the bactericidal effect of P-07 exceeded that of levofloxacin ( Figure 7 C and D). Figure 7 As shown in E and F, the wound size of each group gradually decreased within 11 days, indicating the healing process of the wound under natural and drug-administered conditions. The weight of mice in each group decreased rapidly in the early stage of modeling and gradually returned to normal levels after the start of treatment (Figure 7G). In order to further verify the efficacy of different therapeutic drugs, hematoxylin and eosin (H&E) staining was used to examine the histopathological changes of the infected site at the end of treatment. The epidermis of the P-07+levofloxacin group recovered better, and no vascular congestion, tissue hemorrhage, or inflammatory cell infiltration was observed. Immunohistochemistry was used to detect the expression level of interleukin-6 (IL-6) in infected tissues ( Figure 7H). The positive signal of IL-6 was stronger in the saline group, indicating that the inflammatory response at the infection site was aggravated. The expression level of IL-6 in the levofloxacin group was comparable to that in the saline group. In contrast, the expression levels of IL-6 in the P-07 and P-07+levofloxacin groups were much lower, similar to those in the uninfected mice. In summary, P-07 significantly reduced the bacterial load and inflammatory response at the site of E. coli infection, thereby promoting wound healing. Compared with levofloxacin or P-07 alone, the combination therapy had a better effect on wound healing.

[0101] The above is an exemplary description of the implementation of the technical solution of the present disclosure. It should be understood that the protection scope of the present disclosure is not limited to the above-mentioned implementation. Any modification, equivalent substitution, improvement, etc. made by those skilled in the art within the spirit and principle of the present disclosure shall be included in the protection scope of the claims of this application.

Claims

1. A class of derivative antimicrobial peptides based on Tritrpticin, wherein the antimicrobial peptide has an amino acid sequence as shown in the general formula (1) or (2): X(YX) n ZZ(XY) n X(1) (YX) n ZZ(XY) n (2) n is selected from 1, 2, and 3; ZZ is selected from the β-turn sequence FPWWWPF or PWWWP; Each X is the same or different and is independently selected from a basic amino acid or an amino acid derivative with a positive charge on the side chain, for example, it can be selected from lysine (Lys, K), arginine (Arg, R), ornithine (Orn, O), homoarginine (Har) and other amino acid derivatives with a positive charge on the side chain; Each Y is the same or different and is independently selected from a hydrophobic amino acid or a hydrophobic amino acid derivative, for example, it can be selected from one of tryptophan (Trp, W), tyrosine (Tyr, Y), phenylalanine (Phe, F), leucine (Leu, L), isoleucine (Ile, I), valine (Val, V), alanine (Ala, A), naphthylalanine (Nal) and other hydrophobic amino acid derivatives.

2. The antimicrobial peptide according to claim 1, characterized in that The amino acid or amino acid derivative is in L-form or D-form.

3. The antimicrobial peptide according to claim 1 or 2, characterized in that The N-terminal group of the antimicrobial peptide is a free amino group or is acetylated; for example, the N-terminal group is an acetylamino group; Preferably, the C-terminal group of the antimicrobial peptide is a carboxyl group or is amidated; for example, the C-terminal group is amidated to become an amide group.

4. The antimicrobial peptide according to any one of claims 1 to 3, characterized in that The antimicrobial peptide has an amino acid sequence as shown below: SEQ ID NO.1(FP-11): KVKVKFPWWWPFKVKVK-NH2; SEQ ID NO.2(P-07): KIKIKPWWWPKIKIK-NH2; Preferably, the antimicrobial peptide is composed of L-type amino acids, the N-terminal group of the antimicrobial peptide is acetylated, and / or the C-terminal group is amidated; Preferably, the antimicrobial peptides FP-11 and P-07 have the following key physicochemical properties: 。 5. A method for preparing the antimicrobial peptide according to any one of claims 1 to 4, wherein the antimicrobial peptide is prepared by solid phase synthesis.

6. An antibacterial drug comprising a therapeutically effective amount of the antibacterial peptide according to any one of claims 1 to 4.

7. Use of the antimicrobial peptide according to any one of claims 1 to 4 in the preparation of antimicrobial drugs.

8. The use according to claim 7, characterized in that: The antibacterial drug is used to treat infections caused by pathogens, such as skin wound infections; Preferably, the pathogen is selected from Gram-positive bacteria or Gram-negative bacteria, for example, at least one selected from Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella aerogenes, Streptococcus, Bacillus or their multi-drug resistant strains; preferably, it is resistant Escherichia coli.

9. A combined antibacterial drug, the active ingredients of which include a therapeutically effective amount of the antimicrobial peptide according to any one of claims 1 to 4 and an antibacterial antibiotic; Preferably, the combined antibacterial drug is used to treat infections caused by pathogens, such as skin wound infections; Preferably, the antibiotic is selected from at least one of polypeptide antibiotics, penicillin antibiotics, β-lactam antibiotics, quinolone antibiotics, cephalosporin antibiotics, and semi-synthetic carbapenem antibiotics; Preferably, the pathogen is selected from Gram-positive bacteria or Gram-negative bacteria, for example, at least one selected from Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella aerogenes, Streptococcus, Bacillus or their multi-drug resistant strains.

10. The combined antibacterial drug according to claim 9, characterized in that: The antimicrobial peptide is antimicrobial peptide P-07; Preferably, it is quinolone antibiotic levofloxacin; Preferably, it is a drug-resistant Escherichia coli.

Images