Using models derived from the X-ray structure of photosystem II, it is shown that the oxygen evolving complex in the S2 state exists in two energetically similar and interconvertible forms. A longstanding question regarding the spectroscopy of the catalyst is thus answered: one form corresponds to the multiline g=2.0 EPR signal (see picture, right; O red, Mn purple, Ca yellow), and the other to the g≥4.1 signals (left).
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.