On the nature of high-spin forms in the S₂ state of the oxygen-evolving complex.

ABSTRACT: The Mn₄CaO _x cluster of the oxygen-evolving complex (OEC) in photosystem II, the site of biological water oxidation, adopts different forms as it progresses through the catalytic cycle of S _i states (i = 0-4) and within each S _i state itself. This has been amply documented by spectroscopy, but the structural basis of spectroscopic polymorphism remains debated. The S₂ state is extensively studied by magnetic resonance spectroscopies. In addition to the common type of g ≈ 2 multiline EPR signal attributed to a low-spin (S = 1/2) form of the manganese cluster, other signals at lower fields (g ≥ 4) associated with the S₂ state arise from higher-spin forms. Resolving the structural

SUBMITTER: Mermigki MA 

PROVIDER: S-EPMC11784572 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature