Structural Changes in the Oxygen-Evolving Complex of Photosystem II Induced by the S1 to S2 Transition: A Combined XRD and QM/MM Study
نویسندگان
چکیده
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.
منابع مشابه
Supporting Information for: Computational Insights on Crystal Structures of the Oxygen- Evolving Complex of Photosystem II with either Ca or Ca Substituted by Sr
SUPPORTING INFORMATION S1. Method details for QM/MM S2. Spin densities for Ca and Sr QM/MM models in the S1, S0, S-1, and S-2 states S3. Interatomic distances for OEC atoms in QM/MM models S4. Structural changes due to Ca/Sr substitution in QM/MM models of the S1, S0, S-1, and S-2 states S5. EXAFS simulations S6. RMSDs of QM/MM models against XRD coordinates S7. QM/MM optimized coordinates QM/M...
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