InterPro : IPR007560

Name  Restriction endonuclease type IV, Mrr Short Name  Restrct_endonuc_IV_Mrr
Type  Domain Description  There are four classes of restriction endonucleases: types I, II,III and IV. All types of enzymes recognise specific short DNA sequences and carry out the endonucleolytic cleavage of DNA to give specific double-stranded fragments with terminal 5'-phosphates. They differ in their recognition sequence, subunit composition, cleavage position, and cofactor requirements [, ], as summarised below:Type I enzymes () cleave at sites remote from recognition site; require both ATP and S-adenosyl-L-methionine to function; multifunctional protein with both restriction and methylase () activities.Type II enzymes () cleave within or at short specific distances from recognition site; most require magnesium; single function (restriction) enzymes independent of methylase.Type III enzymes () cleave at sites a short distance from recognition site; require ATP (but doesn't hydrolyse it); S-adenosyl-L-methionine stimulates reaction but is not required; exists as part of a complex with a modification methylase methylase ().Type IV enzymes target methylated DNA.This entry represents Mrr, a type IV restriction endonuclease involved in the acceptance of modified foreign DNA, restricting both adenine- and cytosine-methylated DNA. Plasmids carrying HincII, HpaI, and TaqI R and M genes are severely restricted in Escherichia colistrains that are Mrr+ []. Mrr appears to be the final effector of the bacterial SOS response, which is not only a vital reply to DNA damage but also constitutes an essential mechanism for the generation of genetic variability that in turn fuels adaptation and resistance development in bacterial populations []. Mrr possesses a cleavage domain that is similar to that found in type II restriction enzymes, however it has an unusual glutamine residue at the central position of the (D/E)-(D/E)XK hallmark of the active site [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

1 Found In

Id Name Short Name Type
IPR016984 Uncharacterised conserved protein UCP031853 UCP031853 Family

1 Parent Features

Id Name Short Name Type
IPR011335 Restriction endonuclease type II-like Restrct_endonuc-II-like Domain

5 Publications

First Author Title Year Journal Volume Pages
Sistla S S-Adenosyl-L-methionine-dependent restriction enzymes. 2004 Crit Rev Biochem Mol Biol 39 1-19
Williams RJ Restriction endonucleases: classification, properties, and applications. 2003 Mol Biotechnol 23 225-43
Waite-Rees PA Characterization and expression of the Escherichia coli Mrr restriction system. 1991 J Bacteriol 173 5207-19
Bujnicki JM Identification of a PD-(D/E)XK-like domain with a novel configuration of the endonuclease active site in the methyl-directed restriction enzyme Mrr and its homologs. 2001 Gene 267 183-91
Aertsen A Mrr instigates the SOS response after high pressure stress in Escherichia coli. 2005 Mol Microbiol 58 1381-91

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)