JBIC Journal of Biological Inorganic Chemistry

, Volume 11, Issue 5, pp 609–616

EPR and redox properties of periplasmic nitrate reductase from Desulfovibrio desulfuricans ATCC 27774

  • Pablo J. González
  • María G. Rivas
  • Carlos D. Brondino
  • Sergey A. Bursakov
  • Isabel Moura
  • José J. G. Moura
Original Paper

DOI: 10.1007/s00775-006-0110-0

Cite this article as:
González, P.J., Rivas, M.G., Brondino, C.D. et al. J Biol Inorg Chem (2006) 11: 609. doi:10.1007/s00775-006-0110-0

Abstract

Nitrate reductases are enzymes that catalyze the conversion of nitrate to nitrite. We report here electron paramagnetic resonance (EPR) studies in the periplasmic nitrate reductase isolated from the sulfate-reducing 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) cofactor and 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.

Keywords

Molybdenum-containing enzymes Periplasmic nitrate reductase Dimethyl sulfoxide reductase family Electron paramagnetic resonance Redox titration 

Abbreviations

Dd

Desulfovibrio desulfuricans ATCC 27774

Ec

Escherichia coli K12

EPR

Electron paramagnetic resonance

Euk-NR

Eukaryotic nitrate reductase

EXAFS

Extended X-ray absorption fine structure

Fdh

Formate dehydrogenase

Mo-bisMGD

Mo bis(molybdopterin guanosine dinucleotide)

MV

Methyl viologen

Nas

Assimilatory nitrate reductase

Nap

Periplasmic nitrate reductase

Nar

Respiratory nitrate reductase

NHE

Normal hydrogen electrode

NR

Nitrate reductase

Pp

Paracoccus pantotrophus

Rs

Rhodobacter sphaeroides

Tricine

N-Tris(hydroxymethyl)methylglycine

Tris

Tris(hydroxymethyl)aminomethane

Supplementary material

775_2006_110_MOESM1_ESM.pdf (145 kb)
Supplementary material

Copyright information

© SBIC 2006

Authors and Affiliations

  • Pablo J. González
    • 1
  • María G. Rivas
    • 1
  • Carlos D. Brondino
    • 2
  • Sergey A. Bursakov
    • 1
  • Isabel Moura
    • 1
  • José J. G. Moura
    • 1
  1. 1.REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e TecnologiaUniversidade Nova de LisboaCaparicaPortugal
  2. 2.Facultad de Bioquímica y Ciencias BiológicasUniversidad Nacional del LitoralSanta FeArgentina

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