Effect of the Ca2+ channel activator CGP 28392 on reactivation of oxygen evolution of Ca(2+)-depleted photosystem II.
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.
Krieger
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Julius-von-Sachs-Institut für Biowissenschaften, Universität Würzburg, Germany.
D002118:Calcium / Q000378:metabolism*; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D009543:Nifedipine / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D011725:Pyridines / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
D002120:Calcium Channel Agonists; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D011725:Pyridines; C040525:CGP 28392; D014700:Verapamil; D009543:Nifedipine; D002122:Calcium Chloride; D010100:Oxygen; D002118:Calcium