Our deepest condolences go out to his family and friends, and to all those who had the privilege of working with him. Rest in peace, Amos. Your work will live on long after you are gone.
PROSITE documentation PDOC00087N-6 Adenine-specific DNA methylases signature
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PURL: https://purl.expasy.org/prosite/documentation/PDOC00087
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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