Experimental determination of upper bound for transition path times in protein folding from single-molecule photon-by-photon trajectories.

ABSTRACT: Transition paths are a uniquely single-molecule property not yet observed for any molecular process in solution. The duration of transition paths is the tiny fraction of the time in an equilibrium single-molecule trajectory when the process actually happens. Here, we report the determination of an upper bound for the transition path time for protein folding from photon-by-photon trajectories. FRET trajectories were measured on single molecules of the dye-labeled, 56-residue 2-state protein GB1, immobilized on a glass surface via a biotin-streptavidin-biotin linkage. Characterization of individual emitted photons by their wavelength, polarization, and absolute and relative time of arrival after picosecond excitation allowed the determination of distributions of FRET efficiencies, donor and

SUBMITTER: Chung HS 

PROVIDER: S-EPMC2715475 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature