Two-state folding over a weak free-energy barrier

Summary, in English

We present a Monte Carlo study of a model protein with 54 amino acids that folds directly to its native three-helix-bundle state without forming any well-defined intermediate state. The free-energy barrier separating the native and unfolded states of this protein is found to be weak, even at the folding temperature. Nevertheless, we find that melting curves to a good approximation can be described in terms of a simple two-state system, and that the relaxation behavior is close to single exponential. The motion along individual reaction coordinates is roughly diffusive on timescales beyond the reconfiguration time for a single helix. A simple estimate based on diffusion in a square-well potential predicts the relaxation time within a factor of two.

• Author: Giorgio Favrin; Anders Irbäck; Björn Samuelsson; Stefan Wallin
• Department/s: Computational Biology and Biological Physics - Undergoing reorganization
• Publishing year: 2003
• Language: English
• Pages: 1457-1465
• Publication/Series: Biophysical Journal
• Volume: 85
• Issue: 3
• Links: http://www.biophysj.org/cgi/content/abstract/85/3/1457
• Document type: Journal article
• Publisher: Cell Press
• Topic: Biophysics
• Status: Published
• ISBN/ISSN/Other: ISSN: 1542-0086