INVESTIGADORES
BRONDINO Carlos Dante
artículos
Título:
EPR and Redox Properties of Periplasmic Nitrate Reductase from Desulfovibrio desulfuricans ATCC 27774
Autor/es:
P. J. GONZÁLEZ; M. G. RIVAS; C. D. BRONDINO; S. A. BURSAKOV; I. MOURA; J. J. G. MOURA
Revista:
JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY
Editorial:
Springer-Verlag
Referencias:
Año: 2006 vol. 11 p. 609 - 616
ISSN:
0949-8257
Resumen:
Nitrate reductases are enzymes that catalyze the conversion of nitrate to nitrite. We report hereelectron paramagnetic resonance (EPR) studies in the periplasmic nitrate reductase isolated from the sulfatereducing bacteria Desulfovibrio desulfuricans ATCC 27774. This protein, belonging to the dimethyl sulfoxide reductase family of mononuclear Mo-containing enzymes, comprises a single 80-kDa subunit and contains a Mo bis(molybdopterin guanosine dinucleotide) cofactorand a [4Fe–4S] cluster. EPR-monitored redox titrations, carried out with and without nitrate in the potential range from 200 to 500 mV, and EPR studies of the enzyme, in both catalytic and inhibited conditions, reveal distinct types of Mo(V) EPR-active species, which indicates that the Mo site presents high coordination flexibility. These studies show that nitrate modulates the redox properties of the Mo active site, but not those of the [4Fe–4S] center. The possible structures and the role in catalysis of the distinct Mo(V) species detected by EPR are discussed.