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Updated: Jun 4, 2026
Dot Blot Assay for Detecting Global N6-Methyladenosine RNA Modification Levels
Published on: February 6, 2026
Enzymatic deamination of the epigenetic base N-6-methyladenine
Siddhesh S Kamat1, Hao Fan, J Michael Sauder
1Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States.
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).
Insights
Researchers discovered a new enzyme, N-6-methyladenine deaminase (6-MAD), that removes methyl groups from bacterial DNA. This enzyme, Bh0637, efficiently converts N-6-methyladenine to hypoxanthine, offering insights into DNA modification and repair mechanisms.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Bacterial DNA methylation, specifically N-6-methyladenine, is crucial for protecting host DNA from restriction enzymes.
- The functional roles of many enzymes within the amidohydrolase superfamily remain uncharacterized.
Purpose of the Study:
- To identify and characterize novel enzymes involved in DNA modification.
- To elucidate the function of previously unknown amidohydrolase superfamily members.
Main Methods:
- Enzyme activity assays were performed to determine the catalytic efficiency (kcat and kcat/Km) of Bh0637.
- Comparative modeling and computational docking were employed to understand enzyme-substrate interactions.
Main Results:
- Two enzymes were identified as catalyzing the deamination of N-6-methyladenine to hypoxanthine and methyl amine.
- The Bacillus halodurans enzyme, Bh0637, demonstrated high catalytic efficiency for N-6-methyladenine deamination.
- Bh0637 exhibited a substrate preference for N-6-methyladenine over adenine, being two orders of magnitude faster.
Conclusions:
- This study reports the first identification and characterization of an N-6-methyladenine deaminase (6-MAD).
- The findings provide a molecular basis for understanding N-6-methyladenine modification in bacterial DNA.
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