Thickness-dependent secondary structure formation of tubelike polymers

TL;DR

This study uses Monte Carlo simulations to explore how the thickness of flexible polymers influences their conformational phases, revealing that thickness constraints promote secondary structures like helices, turns, rings, and rods.

Contribution

It introduces a geometric thickness constraint in polymer models, demonstrating its role in the formation of secondary structures and phase behavior.

Findings

Thickness induces secondary structures such as helices and turns.

Conformational phases depend on temperature and thickness.

Ringlike and rodlike conformations are also prominent.

Abstract

By means of sophisticated Monte Carlo methods, we investigate the conformational phase diagram of a simple model for flexible polymers with explicit thickness. The thickness constraint, which is introduced geometrically via the global radius of curvature of a polymer conformation, accounts for the excluded volume of the polymer and induces cooperative effects supporting the formation of secondary structures. In our detailed analysis of the temperature and thickness dependence of the conformational behavior for classes of short tubelike polymers, we find that known secondary-structure segments like helices and turns, but also ringlike conformations and stiff rods are dominant intrinsic topologies governing the phase behavior of such cooperative tubelike objects. This shows that the thickness constraint is indeed a fundamental physical parameter that allows for a classification of generic polymer structures.