Nitrite reduction by xanthine oxidase family enzymes: a new class of nitrite reductases,
Maia, L. B., and Moura J. J.
, J Biol Inorg Chem, Mar, Volume 16, Number 3, p.443-60, (2011)
AbstractMammalian xanthine oxidase (XO) and Desulfovibrio gigas aldehyde oxidoreductase (AOR) are members of the XO family of mononuclear molybdoenzymes that catalyse the oxidative hydroxylation of a wide range of aldehydes and heterocyclic compounds. Much less known is the XO ability to catalyse the nitrite reduction to nitric oxide radical (NO). To assess the competence of other XO family enzymes to catalyse the nitrite reduction and to shed some light onto the molecular mechanism of this reaction, we characterised the anaerobic XO- and AOR-catalysed nitrite reduction. The identification of NO as the reaction product was done with a NO-selective electrode and by electron paramagnetic resonance (EPR) spectroscopy. The steady-state kinetic characterisation corroborated the XO-catalysed nitrite reduction and demonstrated, for the first time, that the prokaryotic AOR does catalyse the nitrite reduction to NO, in the presence of any electron donor to the enzyme, substrate (aldehyde) or not (dithionite). Nitrite binding and reduction was shown by EPR spectroscopy to occur on a reduced molybdenum centre. A molecular mechanism of AOR- and XO-catalysed nitrite reduction is discussed, in which the higher oxidation states of molybdenum seem to be involved in oxygen-atom insertion, whereas the lower oxidation states would favour oxygen-atom abstraction. Our results define a new catalytic performance for AOR-the nitrite reduction-and propose a new class of molybdenum-containing nitrite reductases.
Nitrite reductase activity of rat and human xanthine oxidase, xanthine dehydrogenase and aldehyde oxidase: evaluation of their contribution to the NO formation in vivo,
Maia, L. B., Pereira V., Mira L., and Moura J. J. G.
, Biochemistry, Volume 54, p.685-710, (2015)
NADH oxidase activity of rat and human liver xanthine oxidoreductase: potential role in superoxide production,
Maia, L., Duarte R. O., Ponces-Freire A., Moura J. J., and Mira L.
, J Biol Inorg Chem, Aug, Volume 12, Number 6, p.777-87, (2007)
AbstractTo characterise the NADH oxidase activity of both xanthine dehydrogenase (XD) and xanthine oxidase (XO) forms of rat liver xanthine oxidoreductase (XOR) and to evaluate the potential role of this mammalian enzyme as an O2*- source, kinetics and electron paramagnetic resonance (EPR) spectroscopic studies were performed. A steady-state kinetics study of XD showed that it catalyses NADH oxidation, leading to the formation of one O2*- molecule and half a H(2)O(2) molecule per NADH molecule, at rates 3 times those observed for XO (29.2 +/- 1.6 and 9.38 +/- 0.31 min(-1), respectively). EPR spectra of NADH-reduced XD and XO were qualitatively similar, but they were quantitatively quite different. While NADH efficiently reduced XD, only a great excess of NADH reduced XO. In agreement with reductive titration data, the XD specificity constant for NADH (8.73 +/- 1.36 microM(-1) min(-1)) was found to be higher than that of the XO specificity constant (1.07 +/- 0.09 microM(-1) min(-1)). It was confirmed that, for the reducing substrate xanthine, rat liver XD is also a better O2*- source than XO. These data show that the dehydrogenase form of liver XOR is, thus, intrinsically more efficient at generating O2*- than the oxidase form, independently of the reducing substrate. Most importantly, for comparative purposes, human liver XO activity towards NADH oxidation was also studied, and the kinetics parameters obtained were found to be very similar to those of the XO form of rat liver XOR, foreseeing potential applications of rat liver XOR as a model of the human liver enzyme.
Synthesis and characterization of [S2MoS2Cu(n-SPhF)]2−(n=o, m, p) clusters: Potential 19F-NMR structural probes for Orange Protein,
Maiti, B. K., Avilés T., Moura I., Pauleta S. R., and Moura J. J. G.
, Inorg Chem Commun, Volume 45, p.97-100, (2014)
Designed Metal-ATCUN Derivatives: Redox and Non-redox-Based Applications Relevant for Chemistry, Biology, and Medicine,
Maiti, B. K., Govil N., Kundu T., and J.J.G. Moura
, iScience, Volume 23, p.101792, (2020)
Rearrangement of Mo-Cu-S Cluster Reflects the Structural Instability of Orange Protein Cofactor,
Maiti, B. K., Avilés T., Carepo M. S., Moura I., S.R. Pauleta, and Moura J. J. G.
, Z Anorg Allg Chem, Volume 639, p.1361-1364, (2013)
Insights into the molybdenum/copper heterometallic cluster assembly in the orange protein: probing intermolecular interactions with an artificial metal-binding ATCUN tag,
Maiti, B. K., Almeida R. M., Maia L. B., Moura I., and Moura J. J. G.
, Inorg Chem, Volume 56, p.8900-8911, (2017)
Incorporation of molybdenum in rubredoxin: Models for mononuclear molybdenum enzymes,
Maiti, B. K., Maia L. B., Silveira C., Todorovic S., Carreira C., Carepo M., Grazina R., Moura I., and Moura J. J. G.
, J Biol Inorg Chem, Volume 20, p.821-829, (2015)
Synthesis of [MoS4]2 – M (M = Cu and Cd) clusters: Potential NMR structural probes for orange protein,
Maiti, B. K., Avilés T., Matzapetakis M., Moura I., Pauleta S. R., and Moura J. J. G.
, Eur J Inorg Chem , Volume 2012, p.4159-4166, (2012)
Unusual reduction mechanism of copper in cysteine-rich environment,
Maiti, B. K., Maia L., Moro A. J., Lima J. C., Cordas C., Moura I., and Moura J. J. G.
, Inorg Chem, Volume 57, p.8078-8088, (2018)
One Electron Reduced Square Planar Bis(benzene-1,2-dithiolato) Copper Dianionic Complex and Redox Switch by O2/HO-,
Maiti, B. K., Maia L. B., Pal K., Pakira B., Aviles T., Moura I., Pauleta S. R., Nuñez J. L., Rizzi A. C., Brondino C. D., Sarkar S., and Moura J. J. G.
, Inorg Chem, Volume 53, p.12799-12808, (2014)
Protein-Assisted Formation of Molybdenum Heterometallic Clusters: Evidence for the Formation of S2MoS2−M−S2MoS2 Clusters with M = Fe, Co, Ni, Cu, or Cd within the Orange Protein,
Maiti, B. K., Maia L. B., Pauleta S. R., Moura I., and Moura J. J. G.
, Inorg Chem, Volume 56, p.2210−2220, (2017)
Kinetic and structural studies of aldehyde oxidoreductase from Desulfovibrio gigas reveal a dithiolene-based chemistry for enzyme activation and inhibition by H2O2,
Marangon, J., Correia H. D., Brondino C. D., Moura J. J. G., Romao M. J., Gonzalez P. J., and Santos-Silva T.
, PLoS One, Volume 8, p.e83234, (2013)