Photooxidation of high-potential (c559, c556) and low-potential (c552) hemes in the cytochrome subunit of Rhodopseudomonas viridis reaction center. Characterization by FTIR spectroscopy. |
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Authors: | E Nabedryk C Berthomieu A Verméglio J Breton |
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Affiliation: | DBCM/SBE, CEN Saclay, Gif-sur-Yvette, France. |
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Abstract: | The photooxidation of c559, c556 and c552 hemes in Rhodopseudomonas viridis cytochrome has been characterized by light-induced FTIR difference spectroscopy. Apart from the common features at 1659 cm-1 and 1561/1551 cm-1 which could arise from one (or possibly two) peptide bond(s), no evidence for major structural rearrangement of the polypeptide backbone was observed. A significant difference with respect to redox-induced FTIR spectra of cytochrome c is the absence of the Tyr marker at 1514/1518 cm-1 in Rps. viridis cytochrome, indicating that the localized shift of a Tyr side chain observed between ferro- and ferri-cytochrome c does not occur in Rps. viridis cytochrome. |
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