Member database | Pfam |
Pfam type | domain |
Short name | MmeI_hel |
Author | Paysan-Lafosse T;0000-0001-5663-0894 |
Sequence Ontology | 0000417 |
Description
Type IIL Restriction-Modification Enzyme MmeI is a large enzyme that integrates DNA recognition and methyltransferase and endonuclease activities within the same polypeptide
[3, 2, 1]. MmeI is composed of five domains. An N-terminal endonuclease domain (residues 1-155), connects to a DNA-methyltransferase domain (MTase, residues 301-320) via a multi-helical spacer (residues 156-300). These are followed by the target recognition domain (TRD, residues 621-825), and a final C-terminal helical bundle (residues 826-919)
[4]. The endonuclease cuts the two DNA strands at one site simultaneously with enzyme bound at two sites interacting to accomplish the cleavage
[3]. This domain corresponds to the multi-helical spacer. It is thought to play a key role in positioning the endonuclease cleavage domain correctly.
References
1.Two intertwined methylation activities of the MmeI restriction-modification class-IIS system from Methylophilus methylotrophus. Tucholski J, Zmijewski JW, Podhajska AJ. Gene 223, 293-302, (1998). PMID: 9858752
2.Isolation and computer-aided characterization of MmeI, a type II restriction endonuclease from Methylophilus methylotrophus. Boyd AC, Charles IG, Keyte JW, Brammar WJ. Nucleic Acids Res 14, 5255-74, (1986). PMID: 3016643