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Single-molecule fluorescence experiments determine protein folding transition path times.

ABSTRACT: The transition path is the tiny fraction of an equilibrium molecular trajectory when a transition occurs as the free-energy barrier between two states is crossed. It is a single-molecule property that contains all the mechanistic information on how a process occurs. As a step toward observing transition paths in protein folding, we determined the average transition-path time for a fast- and a slow-folding protein from a photon-by-photon analysis of fluorescence trajectories in single-molecule Förster resonance energy transfer experiments. Whereas the folding rate coefficients differ by a factor of 10,000, the transition-path times differ by a factor of less than 5, which shows that a fast- and a slow-folding protein take almost the same time to fold when folding actually happens. A very simple model based on energy landscape theory can explain this result.

SUBMITTER: Chung HS

PROVIDER: S-EPMC3878298 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

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Single-molecule fluorescence experiments determine protein folding transition path times.

Chung Hoi Sung HS McHale Kevin K Louis John M JM Eaton William A WA

Science (New York, N.Y.) 20120201 6071

The transition path is the tiny fraction of an equilibrium molecular trajectory when a transition occurs as the free-energy barrier between two states is crossed. It is a single-molecule property that contains all the mechanistic information on how a process occurs. As a step toward observing transition paths in protein folding, we determined the average transition-path time for a fast- and a slow-folding protein from a photon-by-photon analysis of fluorescence trajectories in single-molecule Fö ...[more]

PMID: 22363011

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