Protein folding in the absence of a clear free-energy barrier

Summary, in English

Many small proteins fold in a two-state manner, the rate-limiting step being the passage of the free-energy barrier separating the unfolded state from the native one. The free-energy barrier is, however, weak or absent for the fastest-folding proteins. Here a simple diffusion picture for such proteins is discussed. It is tested on a model protein that makes a three-helix bundle. Assuming the motion along individual reaction coordinates to be diffusive on timescales beyond the reconfiguration time for a single helix, it is found that the relaxation time can be predicted within a factor of two. It is also shown that melting curves for this protein to a good approximation can be described in terms of a simple two-state system, despite the absence of a clear free-energy barrier.

• Author: Anders Irbäck
• Department/s: Computational Biology and Biological Physics - Undergoing reorganization
• Publishing year: 2003
• Language: English
• Pages: 4867-4878
• Publication/Series: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory
• Volume: 34
• Issue: 10
• Links: http://th-www.if.uj.edu.pl/acta/vol34/abs/v34p4867.htm
• Document type: Journal article
• Publisher: Jagellonian University, Cracow, Poland
• Topic: Biophysics
• Status: Published
• ISBN/ISSN/Other: ISSN: 0587-4254