Femtosecond dynamics of flavoproteins: Charge separation and recombination in riboflavine (vitamin B 2 )-binding protein and in glucose oxidase enzyme

• DOI: 10.1073/pnas.211440398
• Publication Date: 2002-07-26T14:34:10Z
• Authors: Dongping Zhong; Ahmed H. Zewail
• Keywords: Flavoprotein; Flavin adenine dinucleotide

Flavoproteins can function as hydrophobic sites for vitamin B(2) (riboflavin) or, in other structures, with cofactors catalytic reactions such glucose oxidation. In this contribution, we report direct observation of charge separation and recombination two flavoproteins: riboflavin-binding protein oxidase. With femtosecond resolution, observed the ultrafast electron transfer from tryptophan(s) to riboflavin protein, reaction times: approximately 100 fs (86% component) 700 (14%). The was take place 8 ps, probed by decay charge-separated state recovery ground state. time scale indicates local structural tightness dynamics occur that fast efficiency more than 99%. contrast, oxidase, between flavin-adenine-dinucleotide tryptophan(s)/tyrosine(s) takes much longer times, 1.8 ps (75%) 10 (25%); corresponding occurs on scales, 30 nanoseconds, is still 97%. contrast scales structurally different proteins (of same family) correlates distinction function: recognition former requires a tightly bound structure (ultrafast dynamics), oxidation-reduction latter prefer formation lives long enough chemistry efficiently. Finally, also studied influence conformations at ionic strengths denaturant concentrations sharp collapse cleft and, gradual change