Glassy dynamics and memory effects in an intrinsically disordered protein construct

TL;DR

This study reveals that intrinsically disordered proteins exhibit glassy dynamics and memory effects similar to globular proteins, due to multiple local structures, supported by experimental observations and a predictive model.

Contribution

It demonstrates for the first time that disordered proteins show glassy relaxation and memory effects, expanding understanding of their dynamic behavior.

Findings

Disordered proteins exhibit logarithmic relaxations.

Memory effects similar to glassy systems are observed.

A model predicts force-dependent relaxation behavior.

Abstract

Glassy, nonexponential relaxations in globular proteins are typically attributed to conformational behaviors that are missing from intrinsically disordered proteins. Yet, we show that single molecules of a disordered-protein construct display two signatures of glassy dynamics, logarithmic relaxations and a Kovacs memory effect, in response to changes in applied tension. We attribute this to the presence of multiple independent local structures in the chain, which we corroborate with a model that correctly predicts the force dependence of the relaxation. The mechanism established here likely applies to other disordered proteins.