The oxidation of plastoquinol by a cytochrome b 6 f complex: A density functional theory study

A. E. Frolov, A. N. Tikhonov

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6 Citations (Scopus)

Abstract

The energy profile and the rate of oxidation of trimethylquinol in a model system including the Fe2S2 cluster of the cytochrome b 6 f complex and the surrounding amino acid residues (Cys134-Thr135-His136-Leu137-Gly138-Cys139, Cys152, Cys154-His155-Gly156-Ser157, Tyr159) were calculated by density functional theory (DFT). The limiting stage of quinol oxidation, namely, the transfer of hydrogen from quinol to the nearest nitrogen atom (His155), was an endoergonic process (ΔE = 10.6 kcal/mol), in which the energy barrier E a = 25.5 kcal/mol had to be overcome. The rate constant for this reaction was evaluated in terms of the Marcus theory using the semiempirical Moser-Dutton equation; the resulting values, k PCET = 40-170s-1, agreed well with the available experimental data.

Original languageEnglish
Pages (from-to)506-508
Number of pages3
JournalRussian Journal of Physical Chemistry A
Volume83
Issue number3
DOIs
Publication statusPublished - Mar 1 2009
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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