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Comparative studies of three different dissimilatory sulfite reductase isolated from desulfovibrio species
178 A
B034
SULFITE REDUCTASE (SiR): SATURATiON MAGNETIZATIQN OF SINGLY AND DOUBLY REDUCED SiR. L. J. Young , J+. M. Siege,L , K. K. Surerus, and E. P. Day, University of Minnesota, Minneapolis, MN 55455. Duke University Medical Center, Durham, NC 27705, USA. The [4Fe-4S] cluster of singly reduced SiR(l-) is diamagnetic and the siroheme has integer spin. We have determined the system spin of 57Fe enriched SiR(l-) to be S-2 using saturation magnetization data combined with EPR and Mijssbauer spectra. The isomeric shift of the siroheme (.55 mm/s) lies below the range of isomeric shifts of high spin ferrous sites. In doubly reduced SiR(2-) the [4Fe-4S] cluster is spin S-1/2 and the siroheme is high spin ferrous (S=2). Our magnetization study of SiR(2-) indicates weak antiferromagnetic coupling consistent Chloride with previous interpretations of MBssbauer and EPR spectra. does not affect these results.
B035
COMPARATIVE STUDIES OF THREE DIFFERENT DISSIMILATORY SULFITE REDUCTASES ISOLATED FROM DESULFOVIBRIO SPECIES. A. R. Linol, G.Fauaue2, J.LeGall13, B.H. Huvnh4and I. Moural. 1 Centro de Quimica Estrutural, Complexo I, I.S.T., Av. Rovisco Pais, 1%96oa Codex PORTUGAL; 2 Section Enzymologie et Biochimie Ba$tCrienne, ARBS, CEN, Cadarache, 13108 Saint-Paul-LezSchool of Chemical Sciences, Department of Biochemistry, Durance CEDEX, FRANCE; University of Georgia, Athens, GA 30602, USA;4 Department of Physics, Emory University, Atlanta, GA 30322, USA. The utilization of sulfite in sulfate reducing bacteria is carried out by dissimilatory sulfite reductases which can be of three different types: desulforubidin, desulfoviridin and desulfofucsidin. They have different U.V./visible contains mainly spectra and different prosthetic groups content. Desulfoviridin siroporphyrin and desulforubidin and desulfofucsidin have siroheme. The redox properties of the three different types of dissimilatory sulfite reductases are compared as well as the reactivity towards different external ligands such as S032-, S2-, CO and CN‘. Work supported by INIC, JNICT and NSF.
B034
SULFITE REDUCTASE (SiR): SATURATiON MAGNETIZATIQN OF SINGLY AND DOUBLY REDUCED SiR. L. J. Young , J+. M. Siege,L , K. K. Surerus, and E. P. Day, University of Minnesota, Minneapolis, MN 55455. Duke University Medical Center, Durham, NC 27705, USA. The [4Fe-4S] cluster of singly reduced SiR(l-) is diamagnetic and the siroheme has integer spin. We have determined the system spin of 57Fe enriched SiR(l-) to be S-2 using saturation magnetization data combined with EPR and Mijssbauer spectra. The isomeric shift of the siroheme (.55 mm/s) lies below the range of isomeric shifts of high spin ferrous sites. In doubly reduced SiR(2-) the [4Fe-4S] cluster is spin S-1/2 and the siroheme is high spin ferrous (S=2). Our magnetization study of SiR(2-) indicates weak antiferromagnetic coupling consistent Chloride with previous interpretations of MBssbauer and EPR spectra. does not affect these results.
B035
COMPARATIVE STUDIES OF THREE DIFFERENT DISSIMILATORY SULFITE REDUCTASES ISOLATED FROM DESULFOVIBRIO SPECIES. A. R. Linol, G.Fauaue2, J.LeGall13, B.H. Huvnh4and I. Moural. 1 Centro de Quimica Estrutural, Complexo I, I.S.T., Av. Rovisco Pais, 1%96oa Codex PORTUGAL; 2 Section Enzymologie et Biochimie Ba$tCrienne, ARBS, CEN, Cadarache, 13108 Saint-Paul-LezSchool of Chemical Sciences, Department of Biochemistry, Durance CEDEX, FRANCE; University of Georgia, Athens, GA 30602, USA;4 Department of Physics, Emory University, Atlanta, GA 30322, USA. The utilization of sulfite in sulfate reducing bacteria is carried out by dissimilatory sulfite reductases which can be of three different types: desulforubidin, desulfoviridin and desulfofucsidin. They have different U.V./visible contains mainly spectra and different prosthetic groups content. Desulfoviridin siroporphyrin and desulforubidin and desulfofucsidin have siroheme. The redox properties of the three different types of dissimilatory sulfite reductases are compared as well as the reactivity towards different external ligands such as S032-, S2-, CO and CN‘. Work supported by INIC, JNICT and NSF.