The Nitrile-Forming Enzyme 7-Cyano-7-Deazaguanine Synthase from Geobacillus kaustophilus: A Reverse Nitrilase?

Chembiochem. 2015 Nov 2;16(16):2373-8. doi: 10.1002/cbic.201500335. Epub 2015 Oct 14.

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.

Keywords: 7-cyano-7-deazaguanine synthase; AMP forming; deazapurine; enzyme catalysis; nitrile formation; protein structures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Aminohydrolases / chemistry
  • Aminohydrolases / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism*
  • Catalytic Domain
  • Geobacillus / enzymology*
  • Guanosine / analogs & derivatives
  • Guanosine / chemistry
  • Hydrogen-Ion Concentration
  • Molecular Sequence Data
  • Protein Stability
  • Sequence Alignment
  • Substrate Specificity
  • Temperature

Substances

  • 7-cyano-7-deazaguanosine
  • Bacterial Proteins
  • Guanosine
  • Aminohydrolases
  • nitrilase