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Effect of formate on Mössbauer parameters of the non‐heme iron of PS II particles of cyanobacteria
Author(s) -
Semin B.K.,
Loviagina E.R.,
Aleksandrov A.Yu.,
Kaurov Yu.N.,
Novakova A.A.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81263-n
Subject(s) - quadrupole splitting , chemistry , heme , formate , ligand (biochemistry) , mössbauer spectroscopy , sodium dithionite , inorganic chemistry , photochemistry , heme a , crystallography , catalysis , organic chemistry , biochemistry , enzyme , receptor
Mössbauer spectra were measured for PSII particles having an active water‐splitting system. The particles were isolated from the thennophilic cyanobacterium Synechococcus elongatus enriched in 57 Fe. The Mössbauer resonance absorption spectrum is a superposition of 3 doublets with the following quadrupole splitting and chemical shift: 1, δ = 0.40, Δ = 0.85; II, δ = 1.35,Δ =2.35; III, δ = 0.25, Δ = 1.65. The δ and Δ 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 6–559. 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 Mossbauer 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.