Crunching Biofilament Rings

TL;DR

This paper explores the collective mechanical behavior of coupled non-linear monomers in circular biofilaments, revealing multistability, degeneracy, and softening phenomena that influence membrane deformation processes.

Contribution

It introduces the concept of polymorphic crunching in biofilament rings and demonstrates how monomer frustration affects their mechanical properties and membrane interactions.

Findings

Multistability and degeneracy emerge as collective features.

Increasing monomer frustration causes conformational softening.

Cooperative interactions are crucial for membrane fission.

Abstract

We discuss a curious example for the collective mechanical behavior of coupled non-linear monomer units entrapped in a circular filament. Within a simple model we elucidate how multistability of monomer units and exponentially large degeneracy of the filament's ground state emerge as a collective feature of the closed filament. Surprisingly, increasing the monomer frustration, i.e., the bending prestrain within the circular filament, leads to a conformational softening of the system. The phenomenon, that we term polymorphic crunching, is discussed and applied to a possible scenario for membrane tube deformation by switchable dynamin or FtsZ filaments. We find an important role of cooperative inter-unit interaction for efficient ring induced membrane fission.