Relationship among photosystem II carbonic anhydrase, extrinsic polypeptides and manganese cluster

Effects of Photosystem II (PS II) extrinsic polypeptides of oxygen-evolving complex and manganese clusters on PS II carbonic anhydrase (CA) were studi ed with spinach PS II membranes. The result supported that membrane-bound C A is located in the donor side of PSII. The extrinsic polypeptides played a n important role of maintaining CA activity. After removing manganese clust ers, oxygen evolution activity was inhibited, but PSII-CA activity was unch anged. It was concluded that CA activity is independent of the presence of manganese clusters, and was not directly correlated with oxygen evolution a ctivity.