An oxyl/oxo mechanism for oxygen-oxygen coupling in PSII revealed by an x-ray free-electron laser.Suga, M., Akita, F., Yamashita, K., Nakajima, Y., Ueno, G., Li, H., Yamane, T., Hirata, K., Umena, Y., Yonekura, S., Yu, L.J., Murakami, H., Nomura, T., Kimura, T., Kubo, M., Baba, S., Kumasaka, T., Tono, K., Yabashi, M., Isobe, H., Yamaguchi, K., Yamamoto, M., Ago, H., Shen, J.R.
(2019) Science 366: 334-338
- PubMed: 31624207
- DOI: 10.1126/science.aax6998
- Primary Citation of Related Structures:
6JLP, 6JLK, 6JLJ, 6JLM, 6JLL, 6JLO, 6JLN
- PubMed Abstract:
Photosynthetic water oxidation is catalyzed by the Mn 4 CaO 5 cluster of photosystem II (PSII) with linear progression through five S-state intermediates (S 0 to S 4 ). To reveal the mechanism of water ox ...
Photosynthetic water oxidation is catalyzed by the Mn 4 CaO 5 cluster of photosystem II (PSII) with linear progression through five S-state intermediates (S 0 to S 4 ). To reveal the mechanism of water oxidation, we analyzed structures of PSII in the S 1 , S 2 , and S 3 states by x-ray free-electron laser serial crystallography. No insertion of water was found in S 2 , but flipping of D1 Glu 189 upon transition to S 3 leads to the opening of a water channel and provides a space for incorporation of an additional oxygen ligand, resulting in an open cubane Mn 4 CaO 6 cluster with an oxyl/oxo bridge. Structural changes of PSII between the different S states reveal cooperative action of substrate water access, proton release, and dioxygen formation in photosynthetic water oxidation.
Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan. firstname.lastname@example.org email@example.com firstname.lastname@example.org.