Stitched Polypeptides via Ring-Closing Metathesis
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Solution Overview
Problem
Alpha-helical peptides are prone to unraveling and proteolytic degradation, limiting their stability and biological activity in physiological conditions.
Innovation Solution
The development of 'stapled' and 'stitched' polypeptides through ring-closing metathesis reactions to form cross-linked rings, maintaining the alpha-helical conformation and enhancing stability and biological activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alpha-helical peptides are used as therapeutic agents, then biological activity is improved, but stability against proteolytic degradation deteriorates
Solution Approach 1:
The patent applies composite materials by combining peptide sequences with non-peptidic stabilizing moieties (such as alpha-aminoisobutyric acid residues or other conformational constraints) to create hybrid structures. This composite approach maintains the bioactive alpha-helical conformation while adding proteolytic resistance, directly resolving the contradiction between biological activity and stability.
Solution Approach 2:
The patent changes the chemical parameters of the peptide by incorporating unnatural amino acids (like Aib) or modifying existing residues to alter conformational preferences and proteolytic susceptibility. These parameter changes enable the peptide to maintain its active conformation while becoming resistant to degradation, simultaneously improving both biological activity and stability.
2Reliability
If alpha-helical peptides are used as therapeutic agents, then biological activity is improved, but propensity for unraveling increases
Solution Approach 1:
The patent segments the peptide structure by introducing conformational constraints at specific positions along the helix. These constraints (such as cyclic structures or rigid amino acid residues) divide the peptide into stabilized segments that maintain the alpha-helical conformation without requiring the entire chain to remain flexible, thereby preventing unraveling while preserving biological activity.
Solution Approach 2:
The patent changes the conformational parameters of the peptide by incorporating residues with restricted phi/psi angles (like Aib) that enforce alpha-helical geometry. This parameter change locks the peptide into its active conformation, preventing unraveling into random coils while maintaining the bioactive structure.
3Stability of the object's composition
If cross-links are introduced to stabilize peptide conformation, then conformational stability is improved, but structural complexity increases
Solution Approach 1:
The patent applies local quality by introducing conformational constraints only at specific strategic positions within the peptide sequence rather than throughout the entire structure. This localized approach provides sufficient conformational stability to prevent unraveling while minimizing the increase in overall structural complexity, as the constraints are confined to key regions needed for helix stabilization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach effectively constrains the polypeptides to their native alpha-helical structure, increasing resistance to proteolytic cleavage and improving biological activity, as demonstrated by enhanced suppression of malignant growth in animal models.
Implementation Method 1
two olefin-containing sidechains present in a polypeptide chain are covalently joined (e.g., 'stapled together') using a ring-closing metathesis (RCM) reaction to form a cross-linked ring
Data Source
Figure 1A~1D
Figure 2A
Figure 2B
AI summary
The present invention provides inventive stitched polypeptides, pharmaceutical compositions thereof, and methods of making and using inventive stitched polypeptides.