Protein Family Models

Type IIL Restriction-Modification Enzyme MmeI is a large enzyme that integrates DNA recognition and methyltransferase and endonuclease activities within the same polypeptide [2, 3, 4]. 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) [1]. The DNA is embedded between the TRD and the MTase domain. The TRD makes contacts to the DNA bases primarily in the major groove, while the MTase domain makes several contacts to the DNA in the minor groove [1]. This domain corresponds to the DNA-methyltransferase. Structurally, it consists of a twisted beta-sheet flanked by alpha-helices on both sides. Paper describing PDB structure 5hr4. [1]. 27082731. 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. 2016;14:e1002442.. [2]. 18931376. 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. 2008;36:6558-6570.. [3]. 3016643. 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. 1986;14:5255-5274.. [4]. 9858752. Two intertwine. TRUNCATED at 1650 bytes (from Pfam)

Date:

2024-04-03

Restriction-modification (R-M) systems protect a bacterial cell against invasion of foreign DNA by endonucleolytic cleavage of DNA that lacks a site specific modification. The R-M system is a complex containing three polypeptides: M (this family), S (Pfam:PF01420), and R [1]. This family consists of N-6 adenine-specific DNA methylase EC:2.1.1.72 from Type I and Type IC restriction systems. These methylases have the same sequence specificity as their corresponding restriction enzymes. [1]. 9440532. A type IC restriction-modification system in Lactococcus lactis.. Schouler C, Clier F, Lerayer AL, Ehrlich SD, Chopin MC;. J Bacteriol 1998;180:407-411.. [2]. 9593305. Combinational variation of restriction modification. specificities in Lactococcus lactis.. Schouler C, Gautier M, Ehrlich SD, Chopin MC;. Mol Microbiol 1998;28:169-178.. [3]. 9108149. The specificity of sty SKI, a type I restriction enzyme, implies. a structure with rotational symmetry.. Thorpe PH, Ternent D, Murray NE;. Nucleic Acids Res 1997;25:1694-1700. (from Pfam)

Date:

2024-05-02

This domain is probably a methylase. It is associated with the THUMP domain that also occurs with RNA modification domains [1]. [1]. 11295541. THUMP - a predicted RNA-binding domain shared by 4-thiouridine,. pseudouridine synthases and RNA methylases.. Aravind L, Koonin EV;. Trends Biochem Sci 2001;26:215-217. (from Pfam)

Date:

2024-04-03