PF20465

MmeI, helicase spacer domain

Pfam entry
Member databasePfam
Pfam typedomain
Short nameMmeI_hel
Author Paysan-Lafosse T;0000-0001-5663-0894
Sequence Ontology0000417

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

3.MmeI: a minimal Type II restriction-modification system that only modifies one DNA strand for host protection. Morgan RD, Bhatia TK, Lovasco L, Davis TB. Nucleic Acids Res 36, 6558-70, (2008). PMID: 18931376

4.Structure of Type IIL Restriction-Modification Enzyme MmeI in Complex with DNA Has Implications for Engineering New Specificities. Callahan SJ, Luyten YA, Gupta YK, Wilson GG, Roberts RJ, Morgan RD, Aggarwal AK. PLoS Biol 14, e1002442, (2016). PMID: 27082731

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