title: Relaxation rate for an ultrafast folding protein is independent of chemical denaturant concentration.
abstract: The connection between free-energy surfaces and chevron plots has been investigated in a laser temperature jump kinetic study of a small ultrafast folding protein, the 35-residue subdomain from the villin headpiece. Unlike all other proteins that have been studied so far, no measurable dependence of the unfolding/refolding relaxation rate on denaturant concentration was observed over a wide range of guanidinium chloride concentration. Analysis with a simple Ising-like theoretical model shows that this denaturant-invariant relaxation rate can be explained by a large movement of the major free energy barrier, together with a denaturant- and reaction coordinate-dependent diffusion coefficient.
authors.affiliation: Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
authors.forename: Troy
authors.initials: T
authors.lastname: Cellmer
authors.forename: Eric R
authors.initials: ER
authors.lastname: Henry
authors.forename: Jan
authors.initials: J
authors.lastname: Kubelka
authors.forename: James
authors.initials: J
authors.lastname: Hofrichter
authors.forename: William A
authors.initials: WA
authors.lastname: Eaton
mesh_terms: D007700:Kinetics; D008954:Models, Biological; D011489:Protein Denaturation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D013997:Time Factors
chemical_list: D011506:Proteins