On the Helix-Coil transition in grafted chains

TL;DR

This paper investigates how grafting short peptides to surfaces affects their helix-coil transition, revealing that grafting sharpens the transition, raises the transition temperature, and induces an all-or-nothing behavior due to boundary energy changes, attractions, and crowding effects.

Contribution

It provides a detailed analysis of how surface grafting modifies the helix-coil transition in peptides, highlighting the combined effects of boundary energy, van der Waals attraction, and crowding.

Findings

Grafting induces an all-or-nothing transition behavior.

Transition temperature increases with grafting density.

The transition sharpens as grafting density grows.

Abstract

The helix-coil transition is modified by grafting to a surface. This modification is studied for short peptides capable of forming $\alpha$-helices. Three factors are involved: (i) the grafting can induced change of the boundary free energy of the helical domain (ii) the van der Waals attraction between the helices and (iii) the crowding induced stretching of the coils. As a result the helix-coil transition acquires ``all or nothing'' characteristics. In addition the transition temperature is elevated and the transition itself sharpens as the grafting density increases.