PROSITE documentation PDOC00087N-6 Adenine-specific DNA methylases signature
N-6 adenine-specific DNA methylases (EC 2.1.1.72) (A-Mtase) are enzymes that specifically methylate the amino group at the C-6 position of adenines in DNA. Such enzymes are found in the three existing types of bacterial restriction-modification systems (in type I system the A-Mtase is the product of the hsdM gene, and in type III it is the product of the mod gene). All of these enzymes recognize a specific sequence in DNA and methylate an adenine in that sequence.
It has been shown [1,2,3,4] that A-Mtases contain a conserved motif Asp/Asn-Pro-Pro-Tyr/Phe in their N-terminal section, this conserved region could be involved in substrate binding or in the catalytic activity. We have derived a pattern from that motif.
Note:N-4 cytosine-specific DNA methylases, which are probably enzymatically related to A-Mtases, also include a conserved Pro-Pro dipeptide but the residues around them are sufficiently different to allow the derivation of a pattern specific to these enzymes.
Expert(s) to contact by email: Last update:December 2004 / Pattern and text revised.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Loenen W.A.M. Daniel A.S. Braymer H.D. Murray N.E. |
| Title | Organization and sequence of the hsd genes of Escherichia coli K-12. | |
| Source | J. Mol. Biol. 198:159-170(1987). | |
| PubMed ID | 3323532 |
| 2 | Authors | Narva K.E. Van Etten J.L. Slatko B.E. Benner J.S. |
| Title | The amino acid sequence of the eukaryotic DNA [N6-adenine]methyltransferase, M.CviBIII, has regions of similarity with the prokaryotic isoschizomer M.TaqI and other DNA [N6-adenine] methyltransferases. | |
| Source | Gene 74:253-259(1988). | |
| PubMed ID | 3248728 |
| 3 | Authors | Lauster R. |
| Title | Evolution of type II DNA methyltransferases. A gene duplication model. | |
| Source | J. Mol. Biol. 206:313-321(1989). | |
| PubMed ID | 2541254 |
| 4 | Authors | Timinskas A. Butkus V. Janulaitis A. |
| Title | Sequence motifs characteristic for DNA [cytosine-N4] and DNA [adenine-N6] methyltransferases. Classification of all DNA methyltransferases. | |
| Source | Gene 157:3-11(1995). | |
| PubMed ID | 7607512 |
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