TY - JOUR
T1 - Effect of Chloride Depletion on the Magnetic Properties and the Redox Leveling of the Oxygen-Evolving Complex in Photosystem II
AU - Amin, Muhamed
AU - Pokhrel, Ravi
AU - Brudvig, Gary W.
AU - Badawi, Ashraf
AU - Obayya, S. S.A.
N1 - Funding Information:
We thank Dr. Sandra Luber, Dr. Marilyn Gunner, and Dr. Dimitrios A. Pantazis for helpful discussions. We acknowledge financial support from the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, U.S. Department of Energy (DE-SC0001423). Biochemical work was supported by the Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences (Grant DEFG02-05ER15646 to G.W.B.).
Publisher Copyright:
© 2016 American Chemical Society.
Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 2016/5/12
Y1 - 2016/5/12
N2 - Chloride is an essential cofactor in the oxygen-evolution reaction that takes place in photosystem II (PSII). The oxygen-evolving complex (OEC) is oxidized in a linear four-step photocatalytic cycle in which chloride is required for the OEC to advance beyond the S2 state. Here, using density functional theory, we compare the energetics and spin configuration of two different states of the Mn4CaO5 cluster in the S2 state: state A with Mn13+ and B with Mn43+ with and without chloride. The calculations suggest that model B with an S = 5/2 ground state occurs in the chloride-depleted PSII, which may explain the presence of the EPR signal at g = 4.1. Moreover, we use multiconformer continuum electrostatics to study the effect of chloride depletion on the redox potential associated with the S1/S2 and S2/S3 transitions.
AB - Chloride is an essential cofactor in the oxygen-evolution reaction that takes place in photosystem II (PSII). The oxygen-evolving complex (OEC) is oxidized in a linear four-step photocatalytic cycle in which chloride is required for the OEC to advance beyond the S2 state. Here, using density functional theory, we compare the energetics and spin configuration of two different states of the Mn4CaO5 cluster in the S2 state: state A with Mn13+ and B with Mn43+ with and without chloride. The calculations suggest that model B with an S = 5/2 ground state occurs in the chloride-depleted PSII, which may explain the presence of the EPR signal at g = 4.1. Moreover, we use multiconformer continuum electrostatics to study the effect of chloride depletion on the redox potential associated with the S1/S2 and S2/S3 transitions.
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U2 - 10.1021/acs.jpcb.6b03545
DO - 10.1021/acs.jpcb.6b03545
M3 - Article
C2 - 27077688
AN - SCOPUS:84969695659
VL - 120
SP - 4243
EP - 4248
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 18
ER -