Comparative EPR and redox studies of three prokaryotic enzymes of the xanthine oxidase family: quinoline 2-oxidoreductase, quinaldine 4-oxidase, and isoquinoline 1-oxidoreductase.

  title={Comparative EPR and redox studies of three prokaryotic enzymes of the xanthine oxidase family: quinoline 2-oxidoreductase, quinaldine 4-oxidase, and isoquinoline 1-oxidoreductase.},
  author={C. Canne and I. Stephan and J. Finsterbusch and F. Lingens and R. Kappl and S. Fetzner and J. Hüttermann},
  volume={36 32},
For three prokaryotic enzymes of the xanthine oxidase family, namely quinoline 2-oxidoreductase, quinaldine 4-oxidase, and isoquinoline 1-oxidoreductase, the electron transfer centers were investigated by electron paramagnetic resonance. The enzymes are containing a molybdenum-molybdopterin cytosine dinucleotide cofactor, two distinct [2Fe-2S] clusters and, apart from isoquinoline 1-oxidoreductase, a flavin adenine dinucleotide. The latter cofactor yields two different organic radical signals… Expand
Xanthine dehydrogenase from Pseudomonas putida 86: specificity, oxidation-reduction potentials of its redox-active centers, and first EPR characterization.
The EPR features of the redox-active centers of P. putida XDH are very similar to those of eukaryotic XDHs/xanthine oxidases, suggesting that the environment of each center and their functionality are analogous in these enzymes. Expand
Redox Centers of 4-Hydroxybenzoyl-CoA Reductase, a Member of the Xanthine Oxidase Family of Molybdenum-containing Enzymes*
A catalytic cycle is proposed that takes into account the common properties of molybdenum cofactor enzymes and the special one-electron chemistry of dehydroxylation of phenolic compounds. Expand
Aldehyde oxidoreductase activity in Desulfovibrio alaskensis NCIMB 13491 EPR assignment of the proximal [2Fe-2S] cluster to the Mo site.
A novel molybdenum iron-sulfur-containing aldehyde oxidoreductase (AOR) belonging to the xanthine oxidase family was isolated and characterized from the sulfate-reducing bacterium DesulfovibrioExpand
4‐Hydroxybenzoyl‐Coenzyme A Reductase
The dehydroxylating 4-hydroxybenzoyl-CoA reductase (HBCR) plays an important role in the degradation of para-hydroxylated aromatic compounds in anaerobic bacteria. The enzyme catalyzes the removal ofExpand
Active site geometry and substrate recognition of the molybdenum hydroxylase quinoline 2-oxidoreductase.
The structural comparison of Qor with the allopurinol-inhibited xanthine dehydrogenase from Rhodobacter capsulatus allows direct insight into the mechanism of substrate recognition and the identification of putative catalytic residues. Expand
The Mechanism of Assembly and Cofactor Insertion into Rhodobacter capsulatus Xanthine Dehydrogenase*
Amino acid substitutions at two cysteine residues coordinating FeSI of the two [2Fe-2S] clusters of the enzyme demonstrate that an incomplete assembly of FeSI impairs the formation of the XDH (αβ)2 heterotetramer and, thus, insertion of Moco into the enzyme. Expand
Regioselective aromatic hydroxylation of quinaldine by water using quinaldine 4-oxidase in recombinant Pseudomonas putida
An alternative approach based on molybdenum (Mo)-containing dehydrogenases, which produce, rather than consume, reducing equivalents in the course of substrate hydroxylation and use water as the oxygen donor is discussed. Expand
Selenium-containing xanthine dehydrogenase from Eubacterium barkeri.
Reconstitution experiments of xanthine dehydrogenase activity by addition of selenide and selenite performed with cyanide-inactivated enzyme and with chloramphenicol-treated cells indicated that selenium is not attached to the protein in a covalently bound form such as selenocysteine. Expand
Structural Analysis of Quinoline 2-Oxidoreductase from Pseudomonas putida 86
The crystal structure of the Quinoline 2-Oxidoreductase (Qor), a member of the molybdenum hydroxylase family, was solved at 1.8 A resolution and Mutational analysis showed that only one of the observed AR1-λN contacts is biologically significant. Expand
Functional expression of the quinoline 2-oxidoreductase genes (qorMSL) in Pseudomonas putida KT2440 pUF1 and in P. putida 86-1 deltaqor pUF1 and analysis of the Qor proteins.
Release of CMP upon acidic hydrolysis of the Qor proteins suggested the presence of the MCD form of the pyranopterin cofactor; the CMP contents of the three enzymes were similar. Expand