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pubmed:abstractText |
The effect of the Calcium channel activator, CGP 28392, on the reactivation of oxygen evolution in Ca(2+)-depleted Photosystem II (PS II) particles has been investigated. Ca(2+)-binding is associated with a functional water splitting complex of PS II. In the presence of the activator, a low affinity site of Ca(2+)-binding is converted into a high affinity binding site. Following removal of the extrinsic proteins (17 and 23 kDa), any effect of the activator is no longer observed. Ca2+ channel inhibitors can inhibit the Ca(2+)-dependent reactivation of oxygen evolution. The activator partially protects against this type of inhibition. It is suggested that the extrinsic proteins form a Ca2+ channel-like structure at the donor side of PS II.
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