ePrints@IIScePrints@IISc Home | About | Browse | Latest Additions | Advanced Search | Contact | Help

Mechanistic insights into type III restriction enzymes

Raghavendra, Nidhanapati K and Bheemanaik, Shivakumara and Rao, Desirazu N (2012) Mechanistic insights into type III restriction enzymes. In: Frontiers in Bioscience, 17 . pp. 1094-1107.

[img] PDF
TypeIII_FBS.pdf - Published Version
Restricted to Registered users only

Download (815kB) | Request a copy
Official URL: http://www.bioscience.org/2012/v17/af/3975/list.ht...


Type III restriction-modification (R-M) enzymes need to interact with two separate unmethylated DNA sequences in indirectly repeated, head-to-head orientations for efficient cleavage to occur at a defined location next to only one of the two sites. However, cleavage of sites that are not in head-to-head orientation have been observed to occur under certain reaction conditions in vitro. ATP hydrolysis is required for the long-distance communication between the sites prior to cleavage. Type III R-M enzymes comprise two subunits, Res and Mod that form a homodimeric Mod(2) and a heterotetrameric Res(2)Mod(2) complex. The Mod subunit in M-2 or R2M2 complex recognizes and methylates DNA while the Res subunit in R2M2 complex is responsible for ATP hydrolysis, DNA translocation and cleavage. A vast majority of biochemical studies on Type III R-M enzymes have been undertaken using two closely related enzymes, EcoP1I and EcoP15I. Divergent opinions about how the long-distance interaction between the recognition sites exist and at least three mechanistic models based on 1D- diffusion and/or 3D-DNA looping have been proposed.

Item Type: Journal Article
Publication: Frontiers in Bioscience
Publisher: Frontiers in Bioscience
Additional Information: Copyright of this article belongs to Frontiers in Bioscience.
Keywords: Restriction-modification system;DNA translocation;ATP hydrolysis;DNA looping;Methyltransferase;Endonuclease;Review
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 09 Mar 2012 10:26
Last Modified: 30 Mar 2012 11:31
URI: http://eprints.iisc.ac.in/id/eprint/43864

Actions (login required)

View Item View Item