310-Helical Peptide Stabilization via Triazole Crosslinking

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Solution Overview

Problem

Current methods for stabilizing 310-helices in peptides often distort the helical conformation and lack effective thermal stabilization, while also having limited aqueous solubility, which hampers their utility in biologically relevant applications.

Innovation Solution

The use of a copper(I)-catalyzed azide-alkyne cycloaddition reaction to form a triazole-derived side chain-to-side chain crosslink in 310-helical peptides, which maintains the conformational integrity and enhances thermal stability and aqueous solubility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional crosslinking methods (e.g., metathesis derived olefinic bridges) are used to stabilize 310-helices, then thermal stability is improved, but the backbone conformation is distorted and H-bonds are broken

Engineering Contradiction:
Improvethermal stabilityVSAvoidbackbone conformation
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The patent introduces a p-phenylenediacetic acid bridge as an intermediary crosslinking agent that connects side chains without directly distorting the backbone. This mediator allows thermal stabilization while preserving the native 310-helical conformation and intramolecular H-bonding pattern.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The crosslinking is performed locally at specific positions (i→i+3 or i→i+4) along the peptide chain, allowing stabilization of the helical structure without globally distorting the backbone conformation. The localized crosslinks maintain local H-bonding while providing overall thermal stability.

Inventive Principle:
Principle #3Local quality

2Shape

If α,α-disubstituted amino acids (e.g., Aib, Api) are used to form crosslinked 310-helices, then helix regularity is improved, but the dihedral angles of neighbouring residues are distorted away from ideality

Engineering Contradiction:
Improvehelix regularityVSAvoiddihedral angle precision
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent uses proteinogenic amino acids with standard dihedral angles as the primary building blocks, avoiding the need for non-natural α,α-disubstituted amino acids. This approach maintains ideal dihedral angles while still achieving helix regularity through the crosslinking pattern and conformational constraints.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the crosslinking strategy from using non-natural amino acids with fixed dihedral angles to using natural amino acids with flexible dihedral angles that can adopt ideal values. The crosslinking parameters (position, geometry) are optimized to maintain helix regularity without constraining dihedral angles.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If hydrocarbon stapling is used to stabilize α-helical peptides, then clinical potential is achieved, but application to 310-helical peptides is limited

Engineering Contradiction:
Improveclinical potentialVSAvoidapplicability to 310-helices
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent develops a universal crosslinking methodology using p-phenylenediacetic acid bridges that can be applied to both α-helical and 310-helical peptides. This multi-functional approach maintains the proven clinical potential of hydrocarbon stapling while extending versatility to 310-helical structures through appropriate positioning of crosslinks at i→i+3 or i→i+4 intervals.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Stability of the object's composition

If side chain-to-side chain cyclization is used to stabilize 310-helices, then conformational stability is improved, but aqueous solubility decreases

Engineering Contradiction:
Improveconformational stabilityVSAvoidaqueous solubility
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent changes the chemical parameters of the crosslinking bridge from hydrophobic hydrocarbon staples to more hydrophilic p-phenylenediacetic acid bridges. This parameter change maintains conformational stability through crosslinking while improving aqueous solubility through the polar character and hydrogen-bonding capability of the diacetic acid groups.

Inventive Principle:
Principle #35Parameter changes

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

This approach results in a conformationally stable 310-helical peptide with improved aqueous solubility and thermal stability, preserving the ideal helical conformation, making it suitable for biologically important recognition processes and therapeutic applications.

Implementation Method 1

The use of a copper(I)-catalyzed azide-alkyne cycloaddition reaction to form a triazole-derived side chain-to-side chain crosslink in 310-helical peptides

Methodology Applied
Scientific EffectCopper(I)-catalyzed azide-alkyne cycloaddition: Catalysis

Implementation Method 2

The 310-helix is defined by intramolecular H-bonds between amino acid residues placed at positions i and i+3

Methodology Applied
Scientific EffectHydrogen bonding:

Data Source

PatentUS9227995B2Peptides
Publication Date: 2016.01.05 DRUG DISCOVERY LAB

AI summary

A peptide which can adopt a 310-helical conformation in which the side chains of two amino acid residues in the peptide backbone are linked by a group comprising an aromatic 5-membered ring.