title: Current status of the role of Cl(-) ion in the oxygen-evolving complex.
abstract: This minireview summarizes the current state of knowledge concerning the role of Cl(-) in the oxygen-evolving complex (OEC) of photosystem II (PSII). The model that proposes that Cl(-) is a Mn ligand is discussed in light of more recent work. Studies of Cl(-) specificity, stoichiometry, kinetics, and retention by extrinsic polypeptides are discussed, as are the results that fail to detect Cl(-) ligation to Mn and results that show a lack of a requirement for Cl(-) in PSII-catalyzed H(2)O oxidation. Mutagenesis experiments in cyanobacteria and higher plants that produce evidence for a correlation between Cl(-) retention and stable interactions among intrinsic and extrinsic polypeptides are summarized, and spectroscopic data on the interaction between PSII and Cl(-) are discussed. Lastly, the question of the site of Cl(-) action in PSII is discussed in connection with the current crystal structures of the enzyme.
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA.
authors.forename: Hana
authors.initials: H
authors.lastname: Popelková
authors.forename: Charles F
authors.initials: CF
authors.lastname: Yocum
mesh_terms: D002712:Chlorides / Q000378:metabolism*; D018360:Crystallography, X-Ray; D000458:Cyanobacteria / Q000737:chemistry; D016296:Mutagenesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D013057:Spectrum Analysis
chemical_list: D002712:Chlorides; D045332:Photosystem II Protein Complex