Enzymatic Deamination of the Epigenetic Base N-6-methyladenine

J Am Chem Soc. 2011 Feb 23;133(7):2080-3. doi: 10.1021/ja110157u. Epub 2011 Jan 28.

Abstract

Two enzymes of unknown function from the amidohydrolase superfamily were discovered to catalyze the deamination of N-6-methyladenine to hypoxanthine and methyl amine. The methylation of adenine in bacterial DNA is a common modification for the protection of host DNA against restriction endonucleases. The enzyme from Bacillus halodurans, Bh0637, catalyzes the deamination of N-6-methyladenine with a k(cat) of 185 s(-1) and a k(cat)/K(m) of 2.5 × 10(6) M(-1) s(-1). Bh0637 catalyzes the deamination of N-6-methyladenine 2 orders of magnitude faster than adenine. A comparative model of Bh0637 was computed using the three-dimensional structure of Atu4426 (PDB code: 3NQB) as a structural template and computational docking was used to rationalize the preferential utilization of N-6-methyladenine over adenine. This is the first identification of an N-6-methyladenine deaminase (6-MAD).

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenine / analogs & derivatives*
  • Adenine / chemistry
  • Amidohydrolases / chemistry*
  • Deamination
  • Kinetics
  • Models, Molecular
  • Molecular Structure
  • Substrate Specificity

Substances

  • Amidohydrolases
  • Adenine
  • 6-methyladenine