Critical fluctuations in proteins native states

TL;DR

This study reveals that proteins in their native state exhibit critical behavior with long-range correlations, suggesting they balance structural stability and dynamic flexibility, akin to systems near a critical point.

Contribution

It demonstrates that protein native states display critical fluctuations and long-range correlations, a novel insight into protein dynamics and stability.

Findings

Correlations in residue displacements extend across entire proteins.

Proteins exhibit maximum susceptibility at certain shapes.

Native states maintain dynamic flexibility despite energy landscape minima.

Abstract

We study a large data set of protein structure ensembles of very diverse sizes determined by nuclear magnetic resonance. By examining the distance-dependent correlations in the displacement of residues pairs and conducting finite size scaling analysis it was found that the correlations and susceptibility behave as in systems near a critical point implying that, at the native state, the motion of each amino acid residue is felt by every other residue up to the size of the protein molecule. Furthermore certain protein's shapes corresponding to maximum susceptibility were found to be more probable than others. Overall the results suggest that the protein's native state is critical, implying that despite being posed near the minimum of the energy landscape, they still preserve their dynamic flexibility.