Stabilization of helical macromolecular phases by confined bending

TL;DR

This study uses replica-exchange simulations to explore how bending constraints influence the formation and stabilization of various helical phases in flexible and semiflexible polymers, shedding light on biological helical structures.

Contribution

It demonstrates that bending restraints significantly stabilize helical phases, providing insights into the structural behavior of biological polymers like DNA and proteins.

Findings

Bending restraints stabilize helical phases.

Multiple conformational phases identified, including helical and bundle structures.

Semiflexible polymers tend to form pronounced helical structures.

Abstract

By means of extensive replica-exchange simulations of generic coarse-grained models for helical polymers, we systematically investigate the structural transitions into all possible helical phases for flexible and semiflexible elastic polymers with self-interaction under the influence of torsion barriers. The competing interactions lead to a variety of conformational phases including disordered helical arrangements, single helices, and ordered, tertiary helix bundles. Most remarkably, we find that a bending restraint entails a clear separation and stabilization of the helical phases. This aids in understanding why semiflexible polymers such as double-stranded DNA tend to form pronounced helical structures and proteins often exhibit an abundance of helical structures, such as helix bundles, within their tertiary structure.