Roles of D1-Glu189 and D1-Glu329 in O2 formation by the water-splitting Mn4Ca cluster in Photosystem II.

During the catalytic step that precedes O-O bond formation in Photosystem II, a water molecule deprotonates and moves next to the water-splitting Mn4CaO5 cluster’s O5 oxo bridge. The relocated oxyg...