Comment on "Chain Length Scaling of Protein Folding Time", PRL 77, 5433 (1996)

TL;DR

This paper critiques a previous study on protein folding times by showing that a simple mesoscopic model can explain the data and challenging the original interpretation of the folding dynamics and critical nucleus size.

Contribution

It demonstrates that a mesoscopic model accounts for observed folding time scaling and disputes the original interpretation of folding dynamics in simplified lattice models.

Findings

A mesoscopic model explains the folding time data.

Disagreement with the original interpretation of folding dynamics.

Challenging the estimated size of the critical folding nucleus.

Abstract

In a recent Letter, Gutin, Abkevich, and Shakhnovich (GAS) reported on a series of dynamical Monte Carlo simulations on lattice models of proteins. Based on these highly simplified models, they found that four different potential energies lead to four different folding time scales tau_f, where tau_f scales with chain length as N^lambda (see, also, Refs. [2-4]), with lambda varying from 2.7 to 6.0. However, due to the lack of microscopic models of protein folding dynamics, the interpretation and origin of the data have remained somewhat speculative. It is the purpose of this Comment to point out that the application of a simple "mesoscopic" model (cond-mat/9512019, PRL 77, 2324, 1996) of protein folding provides a full account of the data presented in their paper. Moreover, we find a major qualitative disagreement with the argumentative interpretation of GAS. Including, the origin of the dynamics, and size of the critical folding nucleus.