title: Structural changes in the oxygen-evolving complex of photosystem II induced by the S1 to S2 transition: A combined XRD and QM/MM study.
abstract: The S1 → S2 transition of the oxygen-evolving complex (OEC) of photosystem II does not involve the transfer of a proton to the lumen and occurs at cryogenic temperatures. Therefore, it is commonly thought to involve only Mn oxidation without any significant change in the structure of the OEC. Here, we analyze structural changes upon the S1 → S2 transition, as revealed by quantum mechanics/molecular mechanics methods and the isomorphous difference Fourier method applied to serial femtosecond X-ray diffraction data. We find that the main structural change in the OEC is in the position of the dangling Mn and its coordination environment.
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Askerka
authors.forename: Jimin
authors.initials: J
authors.lastname: Wang
authors.forename: Gary W
authors.initials: GW
authors.lastname: Brudvig
authors.forename: Victor S
authors.initials: VS
authors.lastname: Batista
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry; D018360:Crystallography, X-Ray; D005583:Fourier Analysis; D008345:Manganese / Q000737:chemistry; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D056831:Coordination Complexes; D045332:Photosystem II Protein Complex; D008345:Manganese; D010100:Oxygen