Going around the Kok cycle of the water oxidation reaction with femtosecond X-ray crystallography.

ABSTRACT: The water oxidation reaction in photosystem II (PS II) produces most of the molecular oxygen in the atmosphere, which sustains life on Earth, and in this process releases four electrons and four protons that drive the downstream process of CO₂ fixation in the photosynthetic apparatus. The catalytic center of PS II is an oxygen-bridged Mn₄Ca complex (Mn₄CaO₅) which is progressively oxidized upon the absorption of light by the chlorophyll of the PS II reaction center, and the accumulation of four oxidative equivalents in the catalytic center results in the oxidation of two waters to dioxygen in the last step. The recent emergence of X-ray free-electron lasers (XFELs) with intense femtosecond X-ray pulses has opened up opportunities to visualize thi

SUBMITTER: Bhowmick A 

PROVIDER: S-EPMC10619448 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature