title: Protein folding triggered by electron transfer.
abstract: Rapid photochemical electron injection into unfolded ferricytochrome c titrated with 2.3 to 4.6 M guanidine hydrochloride (GuHCL) at pH 7 and 40 degrees C produced unfolded ferrocytochrome, which then converted to the folded protein. Two folding phases were observed: a fast process with a time constant of 40 microseconds (4.6 M GuHCL), and a slower phase with a rate constant of 90 +/- 20 per second (2.3 M GuHCL). The activation free energy for the slow step varied linearly with GuHCL concentration; the rate constant, extrapolated to aqueous solution, was 7600 per second. Electron-transfer methods can bridge the nanosecond to millisecond measurement time gap for protein folding.
authors.affiliation: Beckman Institute, California Institute of Technology, Pasadena, 91125, USA.
authors.forename: T
authors.initials: T
authors.lastname: Pascher
authors.forename: J P
authors.initials: JP
authors.lastname: Chesick
authors.forename: J R
authors.initials: JR
authors.lastname: Winkler
authors.forename: H B
authors.initials: HB
authors.lastname: Gray
mesh_terms: D003574:Cytochrome c Group / Q000737:chemistry*; D004583:Electrons; D019791:Guanidine; D006146:Guanidines; D010084:Oxidation-Reduction; D010777:Photochemistry; D011489:Protein Denaturation; D017510:Protein Folding; D013696:Temperature; D013816:Thermodynamics
chemical_list: D003574:Cytochrome c Group; D006146:Guanidines; D019791:Guanidine