Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers.

ABSTRACT: In photosynthetic reaction centers from purple bacteria (PbRC) and the water-oxidizing enzyme, photosystem II (PSII), charge separation occurs along one of the two symmetrical electron-transfer branches. Here we report the microscopic origin of the unidirectional charge separation, fully considering electron-hole interaction, electronic coupling of the pigments, and electrostatic interaction with the polarizable entire protein environments. The electronic coupling between the pair of bacteriochlorophylls is large in PbRC, forming a delocalized excited state with the lowest excitation energy (i.e., the special pair). The charge-separated state in the active branch is stabilized by uncharged polar residues in the transmembrane region and charged residues on the cytochrome c₂

SUBMITTER: Tamura H 

PROVIDER: S-EPMC7368266 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature