We introduce a quantum mechanics/molecular mechanics model of the oxygen-evolving complex of photosystem II in the S1Mn4(IV,III,IV,III) state, where Ca2+is bridged to manganese centers by the carboxylate moieties of D170 and A344 on the basis of the new X-ray diffraction (XRD) model recently reported at 1.9 Å resolution. The model is also consistent with high-resolution spectroscopic data, including polarized extended X-ray absorption fine structure data of oriented single crystals. Our results provide refined intermetallic distances within the Mn cluster and suggest that the XRD model most likely corresponds to a mixture of oxidation states, including species more reduced than those observed in the catalytic cycle of water splitting. © 2011 American Chemical Society.
S1-state model of the O2-evolving complex of photosystem II / Luber, Sandra*; Rivalta, Ivan; Umena, Yasufumi; Kawakami, Keisuke; Shen, Jian-Ren; Kamiya, Nobuo; Brudvig, Gary W.; Batista, Victor S.. - In: BIOCHEMISTRY. - ISSN 0006-2960. - STAMPA. - 50:29(2011), pp. 6308-6311. [10.1021/bi200681q]
S1-state model of the O2-evolving complex of photosystem II
Rivalta, Ivan;
2011
Abstract
We introduce a quantum mechanics/molecular mechanics model of the oxygen-evolving complex of photosystem II in the S1Mn4(IV,III,IV,III) state, where Ca2+is bridged to manganese centers by the carboxylate moieties of D170 and A344 on the basis of the new X-ray diffraction (XRD) model recently reported at 1.9 Å resolution. The model is also consistent with high-resolution spectroscopic data, including polarized extended X-ray absorption fine structure data of oriented single crystals. Our results provide refined intermetallic distances within the Mn cluster and suggest that the XRD model most likely corresponds to a mixture of oxidation states, including species more reduced than those observed in the catalytic cycle of water splitting. © 2011 American Chemical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
