Type I Restriction and Modification Systems

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Nomenclature Genes of Type I R-M Type I R-M Families DNA Cleavage DNA Methylation Control of R-M Subunit Assembly


Introduction to site:

This Internet Site describes Type I Restriction-Modification Systems.

These enzyme were the first discovered of all of the types restriction enzymes and pioneered studies of restriction endonucleases, which eventually led to the discovery of Type II Restriction-Modification, their characterisation as site-specific endonucleases and the development of Genetic Engineering.

Type I R-M enzymes are NOT site-specific endonucleases and have not found a use in Genetic Engineering, which means they have been somewhat neglected over the years.  However, they are a very interesting multisubunit, multifunctional molecular motors with strong relationships to both recombination enzymes such as RecBC and to chromatin remodeling factors in eukaryotes.

Recently, there has been a resurgence of interest in these enzymes, in part spurred by investigations that have addressed some of the early questions first raised by the presence of Restriction-Modification systems (Murray, 2000), but more recently due to the single-molecule studies of the enzymes as molecular motors (Seidel et al., 2004) and a review has recently been published by Loenen et al (2014).

These web pages are a resource primarily aimed at those involved in research in this area, but will also provide useful background information to undergraduates and graduate students.


Contact Information:

You can contact the Web Team and Dr Keith Firman using the details below (please explain you are contacting about the Type I R-M Web pages):

Electronic mail
General Information: keith.firman@typei-rm.info
Online Chat
If I am available I will chat here.

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Last modified on 29 December 2013
Dr Keith Firman
Author Dr Keith Firman.