title: The Nitrile-Forming Enzyme 7-Cyano-7-Deazaguanine Synthase from Geobacillus kaustophilus: A Reverse Nitrilase?
abstract: 7-Cyano-7-deazaguanine synthase (E.C. 6.3.4.20) is an enzyme that catalyzes the formation of a nitrile from a carboxylic acid and ammonia at the expense of ATP. The protein from G. kaustophilus was heterologously expressed, and its biochemical characteristics were explored by using a newly developed HPLC-MS based assay, (31) P NMR, and a fluorescence-based thermal-shift assay. The protein showed the expected high thermostability, had a pH optimum at pH 9.5, and an apparent temperature optimum at 60 °C. We observed strict substrate specificity of QueC for the natural substrate 7-carboxy-7-deazaguanine, and determined AMP and pyrophosphate as co-products of preQ0.
authors.affiliation: Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010, Graz, Austria. margit.winkler@acib.at.
authors.forename: Margit
authors.initials: M
authors.lastname: Winkler
authors.affiliation: Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010, Graz, Austria.
authors.forename: Katharina
authors.initials: K
authors.lastname: Dokulil
authors.affiliation: Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010, Graz, Austria.
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Weber
authors.affiliation: Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010, Graz, Austria.
authors.forename: Tea
authors.initials: T
authors.lastname: Pavkov-Keller
authors.affiliation: Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010, Graz, Austria.
authors.forename: Birgit
authors.initials: B
authors.lastname: Wilding
mesh_terms: D000595:Amino Acid Sequence; D000619:Aminohydrolases / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D020134:Catalytic Domain; D056506:Geobacillus / Q000201:enzymology*; D006151:Guanosine / Q000031:analogs & derivatives / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D055550:Protein Stability; D016415:Sequence Alignment; D013379:Substrate Specificity; D013696:Temperature
chemical_list: C556329:7-cyano-7-deazaguanosine; D001426:Bacterial Proteins; D006151:Guanosine; D000619:Aminohydrolases; C021867:nitrilase
keywords: 7-cyano-7-deazaguanine synthase; AMP forming; deazapurine; enzyme catalysis; nitrile formation; protein structures