Concentration-Temperature Superposition of Helix Folding Rates in Gelatin

TL;DR

This study reveals a universal exponential relationship between helix folding rates, concentration, and temperature in gelatin solutions, supporting a diffuse transition model and indicating first-order kinetics in early helix formation.

Contribution

It introduces a concentration-temperature superposition method that creates a master curve for helix folding rates in gelatin, demonstrating a universal kinetic behavior.

Findings

Universal exponential dependence of folding rate on concentration and temperature

Successful superposition of data into a master curve

Evidence for first-order kinetics in early helix folding

Abstract

We study the kinetics of helix-coil transition in water solutions of gelatin (collagen protein) by optical rotation techniques combined with thermal characterization. By examining the rates of secondary helix folding, and covering a very wide range of solution concentrations, we are able to identify a universal exponential dependence of folding rate on concentration and quench temperature. We demonstrate a new concentration-temperature superposition of data at all temperatures and concentrations, and build the corresponding master curve. The results support the concept of a diffuse helix-coil transition. We find no concentration dependance of the normalized rate constant, suggesting first order (single) kinetics of secondary helix folding dominate in the early stages of renaturation.