ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P65. Nitrate reduction by periplasmic nitrate reductase from Desulfovibrio
desulfuricans
P. J. González a , S. Najmudin a , J. Trincão a , C. Coelho a , A. Mukhopadhyay a , C. C. Romão b ,
M. J. Romão a , C. D. Brondino c , I. Moura a and J. J. G. Moura a
a
Departamento de Quimica, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica
2829-516, Portugal
e-mail: pablo.gonzalez@dq.fct.unl.pt
b
Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal
c
Departmento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral,
Santa Fe 3000, Argentina
The periplasmic nitrate reductase (Nap) from Desulfovibrio desulfuricans ATCC 27774 is a molybdenumcontaining
enzyme from the DMSO reductase family. Recently, it was reported that the Mo ion at the active site
is coordinated by six sulfurs without any OH/H2O molecule directly bound to the Mo ion [1, 2]. EPR
spectroscopy was used to corroborate this key result that determines that Naps would catalyze the nitrate
reduction different to Nar and Euk-NR. Several EPR active Mo(V) species were identified and its role in
catalysis was analyzed [3]. The finding of a new paramagnetic Mo(V) species of the enzyme obtained in
catalytic conditions (turnover species) was used to study the oxidation state and coordination environment of the
Mo-site before it interacts with the substrate.
Refrences:
[1] Najmudin et al. J Biol Inorg Chem 2008, 13(5):737-753.
[2] Dias et al. Struct Fol Des 1999, 7, 65-79.
[3] González et al. J Biol Inorg Chem 2006, 11(5):609-616.
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