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Electron transfer in the c‐type cytochrome subunit of the photosynthetic reaction center of Rhodopseudomonas viridis : ab initio theoretical study
Author(s) -
Ohtsuka Yuhki,
Ohkawa Kazufumi,
Nakatsuji Hiroshi
Publication year - 2001
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/1096-987x(20010415)22:5<521::aid-jcc1023>3.0.co;2-j
Subject(s) - chemistry , heme , ab initio , electron transfer , cytochrome , protein subunit , photosynthetic reaction centre , cytochrome c , stereochemistry , electron transport chain , crystallography , photochemistry , biochemistry , enzyme , organic chemistry , mitochondrion , gene
The pathways of the electron transfers (ETs) within the c‐type cytochrome subunit and from the cytochrome subunit to the oxidized special pair (P + ) in the reaction center of Rhodopseudomonas viridis were studied by calculating the transfer integrals among the chromophores and the bridging amino acid residues by ab initio molecular orbital method. In the cytochrome subunit, the candidate of the bridge molecules was selected by the criterion of the distance from the two neighboring hemes, and the calculated results indicate that the ET occurs directly from a heme to the next heme. From c559, the proximate heme to the special pair, to P + , the ET occurs mainly through TYR L162, which lies halfway between c559 and P + , because of its proper location. Furthermore, the mutation experiments in which TYR L162 was replaced by phenylalanine and threonine were examined by the same theoretical method, and it was shown that the result of the mutation experiment was understood by the difference in the spatial distribution of the MOs between the wild type and mutants, and not by the energy difference of the MOs between donor (or acceptor) and bridge, though the latter factor had often been considered as the main factor controlling the rate of the ET. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 521–527, 2001