Structural Changes Correlated with Magnetic Spin State Isomorphism in the S₂ State of the Mn₄CaO₅ Cluster in the Oxygen-Evolving Complex of Photosystem II.

ABSTRACT: The Mn₄CaO₅ cluster in Photosystem II catalyzes the four-electron redox reaction of water oxidation in natural photosynthesis. This catalytic reaction cycles through four intermediate states (S_i, i = 0 to 4), involving changes in the redox state of the four Mn atoms in the cluster. Recent studies suggest the presence and importance of isomorphous structures within the same redox/intermediate S-state. It is highly likely that geometric and electronic structural flexibility play a role in the catalytic mechanism. Among the catalytic intermediates that have been identified experimentally thus far, there is clear evidence of such isomorphism in the S₂ state, with a high-spin (5/2) (HS) and a low spin (1/2) (LS) form, identified and characterized by t

SUBMITTER: Chatterjee R 

PROVIDER: S-EPMC5201215 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature