Substrate Water Bound to the S2-State of the Mn4OxCa Cluster in Photosystem II Studied by Advanced Pulse EPR Spectroscopy

In The Present Study, We Employed Several Advanced Pulse Epr Techniques To Detect Weak Hyperfine Couplings To Study Substrate Water Binding To The Mn4OXCa Cluster In The S2, State Of Photosystem Ii. Our Data Show That The Hyperfine Coupling Between The 2H And The Mn4OXCa Cluster Is Too Weak To Be Resolved. We Propose That The Information Does Not Allow Make Precise Conclusions About The Mode Of Substrate Water Binding To The Mn4OXCa Cluster. Our Preliminary Data Suggest That More Detailed Information Can Be Obtained From The H2 16O/ H2 17O Exchange Experiments.