Fig. 2: Graphic presentations of water insertion after O2 release.
From: Closing Kok’s cycle of nature’s water oxidation catalysis
a The S4 state based on the XFEL structure of the S3 state6 upon removal of one proton and one electron on Ox; the yellow arrow represents the formation and release of O2 through O5–Ox coupling. b The \({{{\mbox{Im}}}0}^{{-{{\mbox{O}}}}_{2}}\) state derived from the S4 state by removal of O5 and Ox for O2 release. c The Im1 state formed by W3 insertion to Mn1 and W5 binding to Ca. d The Im2 state formed by W3 deprotonation to W2 and binding to Mn3, and W7 binding to Mn4; the green arrow denotes H+ is suggested to be released to the lumen from W1 via Asp61. The routes of the key atomic motions observed during the simulations are marked with blue arrows. The red, yellow, and blue background colors stand for the three basic phases of \({{{\mbox{Im}}}0}^{{-{{\mbox{O}}}}_{2}}\), Im1 and Im2, respectively, which correspond to those in Fig. 3.
