Single-Chain Insulin Analogues with Foreshortened C-Domain
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Solution Overview
Problem
Current insulin formulations face challenges with thermal fibrillation, chemical degradation, and mitogenicity, which affect their stability and efficacy, especially in regions without consistent refrigeration, and can lead to unpredictable glucose fluctuations and increased risk of cancer due to skewed receptor binding affinities.
Innovation Solution
Development of single-chain insulin analogues with foreshortened connecting domains and specific amino acid substitutions, such as Histidine at position B10, to enhance thermodynamic stability, resistance to fibrillation, and reduced cross-binding to IGF-1R, while maintaining a ratio of affinities for insulin receptor isoforms similar to wild-type insulin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wild-type human insulin is used, then it binds to insulin receptors in multiple organs and cells, but it also binds to IGF-1R with lower affinity, causing unintended mitogenic effects and cancer risk
Solution Approach 1:
The patent modifies specific local regions of the insulin molecule (C-domain sequence, amino acid substitutions at positions B10, A8, A21) to alter its binding characteristics. These localized changes create differential affinity for IR-A/IR-B versus IGF-1R, reducing mitogenic effects while preserving glucose-lowering activity.
Solution Approach 2:
The patent changes molecular parameters of insulin including the C-domain length (foreshortened from 36 to 6-11 residues), amino acid sequences, and post-translational modifications. These parameter changes optimize the receptor binding profile to achieve selective activity with reduced IGF-1R cross-binding.
2Reliability
If conventional insulin formulations are used, then they provide glucose control, but they undergo thermal fibrillation and chemical degradation above room temperature, affecting stability and efficacy
Solution Approach 1:
The patent modifies thermal and chemical stability parameters through amino acid substitutions (e.g., at positions A8, A21, B10) and C-domain engineering. These changes increase the energy barrier for fibrillation and degradation reactions, enabling stability above room temperature without refrigeration.
Solution Approach 2:
The patent converts the harmful effect of thermal energy that causes fibrillation into a beneficial feature by designing the protein structure to be inherently resistant to thermal degradation. The foreshortened C-domain and specific amino acid substitutions create a more stable folded structure that resists unfolding at elevated temperatures.
3Reliability
If single-chain insulin analogues with foreshortened C-domains are used, then resistance to thermal degradation is increased, but the duration of action needs to be prolonged while maintaining glucose-lowering activity
Solution Approach 1:
The patent optimizes pharmacokinetic parameters through amino acid substitutions and C-domain modifications that affect receptor binding affinity and internalization rates. These changes extend the duration of action by modifying the time course of glucose-lowering activity while preserving thermal stability.
Solution Approach 2:
The patent creates dynamic control over insulin action through modifications that affect the rate of receptor binding, signal transduction, and clearance. The foreshortened C-domain provides flexibility in optimizing the temporal profile of action while maintaining structural stability.
4Object-generated harmful factors
If amino acid substitutions are made to reduce cross-binding to IGF-1R, then mitogenicity is decreased, but thermodynamic stability and resistance to fibrillation must be maintained
Solution Approach 1:
The patent makes localized amino acid substitutions at specific positions (B10: His/Arg, A8: Lys/Arg, A21: Gly/Ala/Ser) that selectively affect IGF-1R binding without compromising overall structural stability. The C-domain sequence modifications are also localized to achieve the desired binding profile while maintaining folded structure integrity.
Data Source
AI summary
A single-chain insulin analogue containing a basic side chain at position A8 (Arginine, Histidine, Lysine, or Ornithine), a basic side chain at position B29 (Arginine, Histidine, Lysine, or Ornithine), and a foreshortened C-domain of length 6-11 residues is provided. Residues C1 and C2 of the C-domain have a net negative charge of −1 or −2; C3 is chosen from a group consisting of Gly, Ala, Pro, or Ser; and the remaining C-domain segment is successively derived from the C-domain of IGF-II (RRSR (SEQ ID NO: 18), SRRSR (SEQ ID NO: 17), VSRRSR (SEQ ID NO: 16), RVSRRSR (SEQ ID NO: 15), or SRVSRRSR (SEQ ID NO: 13)). A method of treating a patient with diabetes mellitus or obesity comprises administering a physiologically effective amount of the insulin analogue or a physiologically acceptable salt thereof to a patient.