The aims of this proposal are to: (1) identify the exposed and chemically susceptible amino acid residues on the PSII polypeptides after various treatments to selectively remove extrinsic proteins and heterogeneous Mn clusters, (2) identify protein domains capable of being x-linked, (3) characterize the structure of a possible extrinsic domain hetero-trimer complex, and (4) use vibrational spectroscopy and circular dichroism to predict the overall secondary structure of each extrinsic protein. %%% Water oxidation (oxygen evolution) during photosynthesis is one of the key reactions for all the living creatures on this planet. The studies proposed will characterize the interactions among the proteins involved in oxygen evolution in spinach. In contributing to an understanding of protein-protein and protein-metal ion interactions in living systems these studies may lead to the discovery of approaches to the formation of synthetic complexes capable of multielectron catalysis on large scales.
