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| PROSITE documentation PDOC00087 |
N-6 Adenine-specific DNA methylases signature
Description:
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:
Roberts R.J.
Bickle T.
Last update:
December 2004 / Pattern and text revised.
Technical section:
PROSITE method (with tools and information) covered by this documentation:
| N6_MTASE, PS00092; N-6 Adenine-specific DNA methylases signature (PATTERN) |
| Consensus pattern: |
[LIVMAC]-[LIVFYWA]-{DYP}-[DN]-P-P-[FYW]
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| Sequences known to belong to this class detected by the pattern: |
ALL, except for m.HhaII where the second Pro is replaced by Gln and in m.HindIII where that same Pro is replaced by Tyr |
| Other sequence(s) detected in Swiss-Prot: |
33 different proteins that are most probably not A-Mtases, and three hypothetical Escherichia coli proteins that could be A-Mtases. |
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| Matching PDB structures:
1AQI 1AQJ 1EG2 1G38 ... [ALL] |
References:
| 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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