S3 State of the O2-Evolving Complex of Photosystem II: Insights from QM/MM, EXAFS, and Femtosecond X-ray Diffraction
© 2016 American Chemical Society. The oxygen-evolving complex (OEC) of photosystem II has been studied in the S3 state by electron paramagnetic resonance, extended X-ray absorption fine structure (EXAFS), and femtosecond X-ray diffraction (XRD). However, the actual structure of the OEC in the S3 state has yet to be established. Here, we apply hybrid quantum mechanics/molecular mechanics methods and propose a structural model that is consistent with EXAFS and XRD. The model supports binding of water ligands to the cluster in the S2 → S3 transition through a carousel rearrangement around Mn4, inspired by studies of ammonia binding.
Publication Source (Journal or Book title)
Askerka, M., Wang, J., Vinyard, D., Brudvig, G., & Batista, V. (2016). S3 State of the O2-Evolving Complex of Photosystem II: Insights from QM/MM, EXAFS, and Femtosecond X-ray Diffraction. Biochemistry, 55 (7), 981-984. https://doi.org/10.1021/acs.biochem.6b00041