Biochemical evidence for histidine oxidation in photosystem II depleted of the Mn-cluster for O2-evolution.
Flash excitation of Tris-treated photosystem II (PSII) membranes generated a thermoluminescence band peaking at -20 degrees C, indicating that a positively charged oxidizing equivalent is stably accumulated on donor side of PSII even in the absence of the Mn-cluster. This oxidizing equivalent was sensitive to low concentrations of exogenous Mn2+, and its stable accumulation was reversibly inhibited by diethylpyrocarbonate treatment that modifies histidine residues with high specificity. It was inferred that there is a photooxidizable histidine residue(s) on donor side of PSII and it provides a redox-active ligand for Mn.
Ono
T
T
Solar Energy Research Group, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
Inoue
Y
Y
D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D006639:Histidine / Q000378:metabolism*; D066298:In Vitro Techniques; D008345:Manganese / Q000378:metabolism*; D008667:Metalloproteins / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D010944:Plants / Q000378:metabolism*
D008667:Metalloproteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D008345:Manganese; D006639:Histidine; D004047:Diethyl Pyrocarbonate; D010100:Oxygen