IDENTIFICATION OF LYSINE RESIDUES ON PSBP POSSIBLY INVOLVED IN ELECTROSTATIC INTERACTION WITH PSBO IN SPINACH PSII

摘要

The three extrinsic proteins of higher plant Photosystem II (PSII), PsbO, PsbP and PsbQ, play important roles for maximal rates of oxygen evolution under physiological ionic conditions (Seidler 1996). The PsbO protein is needed to maintain the functional structure of the Mn cluster. The PsbP and PsbQ proteins are closely related with the unique requirement of Ca~(2+) and Cl~- for oxygen evolution; the PsbP protein mitigates the demand for Ca~(2+) while the PsbQ protein does for Cl~-.The PsbO proteinassociates directly with PSII, but the PsbP protein cannot directly bind to PSII and associates with PSII only through its interaction with the PsbO protein, and the PsbQ protein functionally associates with PSII only through its electrostatic interaction with both the PsbO and PsbP proteins.