4C7Z

Aldehyde Oxidoreductase from Desulfovibrio gigas (MOP), activated with sodium dithionite and sodium sulfide

Summary for 4C7Z

• Entry DOI: 10.2210/pdb4c7z/pdb
• Related: 4C7Y 4C80
• Descriptor: ALDEHYDE OXIDOREDUCTASE, MAGNESIUM ION, FE2/S2 (INORGANIC) CLUSTER, ... (9 entities in total)
• Functional Keywords: oxidoreductase, molybdenum enzyme, mop, activation, inactivation
• Biological source: DESULFOVIBRIO GIGAS
• Total number of polymer chains: 1
• Total formula weight: 98651.57

Authors

Correia, H.D.,Romao, M.J.,Santos-Silva, T. (deposition date: 2013-09-27, release date: 2014-01-15, Last modification date: 2024-11-06)

Primary citation

Marangon, J.,Correia, H.D.,Brondino, C.D.,Moura, J.J.G.,Romao, M.J.,Gonzalez, P.J.,Santos-Silva, T.
Kinetic and Structural Studies of Aldehyde Oxidoreductase from Desulfovibrio Gigas Reveal a Dithiolene-Based Chemistry for Enzyme Activation and Inhibition by H2O2.
Plos One, 8:83234-, 2013

PubMed Abstract: Mononuclear Mo-containing enzymes of the xanthine oxidase (XO) family catalyze the oxidative hydroxylation of aldehydes and heterocyclic compounds. The molybdenum active site shows a distorted square-pyramidal geometry in which two ligands, a hydroxyl/water molecule (the catalytic labile site) and a sulfido ligand, have been shown to be essential for catalysis. The XO family member aldehyde oxidoreductase from Desulfovibrio gigas (DgAOR) is an exception as presents in its catalytically competent form an equatorial oxo ligand instead of the sulfido ligand. Despite this structural difference, inactive samples of DgAOR can be activated upon incubation with dithionite plus sulfide, a procedure similar to that used for activation of desulfo-XO. The fact that DgAOR does not need a sulfido ligand for catalysis indicates that the process leading to the activation of inactive DgAOR samples is different to that of desulfo-XO. We now report a combined kinetic and X-ray crystallographic study to unveil the enzyme modification responsible for the inactivation and the chemistry that occurs at the Mo site when DgAOR is activated. In contrast to XO, which is activated by resulfuration of the Mo site, DgAOR activation/inactivation is governed by the oxidation state of the dithiolene moiety of the pyranopterin cofactor, which demonstrates the non-innocent behavior of the pyranopterin in enzyme activity. We also showed that DgAOR incubation with dithionite plus sulfide in the presence of dioxygen produces hydrogen peroxide not associated with the enzyme activation. The peroxide molecule coordinates to molybdenum in a η(2) fashion inhibiting the enzyme activity.

PubMed: 24391748
DOI: 10.1371/JOURNAL.PONE.0083234

Experimental method

X-RAY DIFFRACTION (1.55 Å)