Intramolecular alpha-helix-beta-structure-random coil transition in polypeptides. I. Equilibrium case

Area of Science:

• Biochemistry
• Polymer Science
• Physical Chemistry

Background:

• Polypeptides exhibit diverse conformations like alpha-helix, beta-structure, and random coil.
• Understanding conformational transitions is crucial for protein folding and function.
• Surfactant interactions can significantly alter polypeptide structures.

Purpose of the Study:

• To develop a finite homogeneous chain model for polypeptide conformational transitions.
• To investigate the mechanism of surfactant-induced conformational changes in polypeptides.
• To validate the model using experimental data of poly(L-lysine) in the presence of surfactants.

Main Methods:

• Development of a theoretical model for polypeptide chains.
• Simulation of conformational transitions (alpha-helix, beta-structure, random coil).
• Analysis of experimental data on poly(L-lysine) conformational changes induced by surfactants.

Main Results:

• The finite homogeneous chain model successfully describes polypeptide conformational transitions.
• The model accurately predicts surfactant-induced conformational changes in poly(L-lysine).
• Cooperative binding of surfactant ions to polypeptide side groups is identified as the key mechanism.

Conclusions:

• The developed model provides a robust framework for studying polypeptide conformational dynamics.
• Surfactant binding plays a critical role in modulating polypeptide secondary structures.
• The findings have implications for understanding protein-surfactant interactions and biomaterial design.