title: Reevaluation of the stoichiometry of cytochrome b559 in photosystem II and thylakoid membranes.
abstract: The stoichiometry of cytochrome b559 (one or two copies) per reaction center of photosystem II (PSII) has been the subject of considerable debate. The molar ratio of cytochrome b559 has a number of significant implications on our understanding of the functional role of cytochrome b559, the mechanism of electron donation in PSII, and the stoichiometry of the other redox-active, reaction center components. We have reinvestigated the stoichiometry of cytochrome b559 in PSII-enriched and thylakoid membranes, using differential absorbance and electron paramagnetic resonance spectroscopies. The data from both quantitation procedures strongly indicate only one copy of cytochrome b559 per reaction center in PSII-enriched membranes and also suggest one copy of cytochrome b559 per reaction center in thylakoid membranes.
authors.affiliation: Department of Chemistry, Yale University, New Haven, Connecticut 06511.
authors.forename: C A
authors.initials: CA
authors.lastname: Buser
authors.forename: B A
authors.initials: BA
authors.lastname: Diner
authors.forename: G W
authors.initials: GW
authors.lastname: Brudvig
mesh_terms: D003573:Cytochrome b Group / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D007425:Intracellular Membranes / Q000201:enzymology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045332:Photosystem II Protein Complex; D013057:Spectrum Analysis
chemical_list: D003573:Cytochrome b Group; D005609:Free Radicals; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C019313:cytochrome b559