title: Effect of formate on Mössbauer parameters of the non-heme iron of PS II particles of cyanobacteria.
abstract: Mössbauer spectra were measured for PSII particles having an active water-splitting system. The particles were isolated from the thermophilic cyanobacterium Synechococcus elongatus enriched in 57Fe. The Mössbauer resonance absorption spectrum is a superposition of 3 doublets with the following quadrupole splitting and chemical shift: 1, delta = 0.40, delta = 0.85; II, delta = 1.35, delta = 2.35; III, delta = 0.25, delta = 1.65. The delta and delta values of doublets I, II, III are characteristic of proteins with iron-sulphur center, non-heme iron of the reaction center of higher plants and of the oxidized cytochrome b-559. Treatment with sodium formate to remove bicarbonate affects only the doublet of non-heme iron, causing its quadrupole splitting to reduce to 1.75 and the chemical shift to reduce to 0.90. After washing out the formate, the Mössbauer spectrum of non-heme iron is restored. The data suggest that bicarbonate is a ligand for the non-heme iron of the reaction center of cyanobacteria.
authors.affiliation: Department of Biophysics, Faculty of Biology, University of Moscow, USSR.
authors.forename: B K
authors.initials: BK
authors.lastname: Semin
authors.forename: E R
authors.initials: ER
authors.lastname: Loviagina
authors.lastname: Aleksandrov AYu
authors.lastname: Kaurov YuN
authors.forename: A A
authors.initials: AA
authors.lastname: Novakova
mesh_terms: D001639:Bicarbonates / Q000378:metabolism*; D000458:Cyanobacteria / Q000378:metabolism*; D005561:Formates / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism; D007501:Iron / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000187:drug effects / Q000378:metabolism*; D015204:Spectroscopy, Mossbauer; D013696:Temperature
chemical_list: D001639:Bicarbonates; D005561:Formates; D045322:Photosynthetic Reaction Center Complex Proteins; C030544:formic acid; D007501:Iron; D010100:Oxygen