Biochemical and physical characterization of exonuclease V from Escherichia coli. Comparison of the catalytic activities of the RecBC and RecBCD enzymes.
Biochemical evidence is presented that confirms exonuclease V of Escherichia coli consists of three distinct subunits encoded by the recB, recC, and recD genes. The recD gene encodes a Mr 60,000 polypeptide and physically maps 3' to the recB structural gene. The role of the recD subunit in exonuclease V function has been examined by comparing the catalytic activities of the purified RecBCD enzyme with the RecBC enzyme. The RecBC enzyme retains significant levels of DNA-dependent ATPase activity and DNA helicase activity. Endonucleolytic activity on single-stranded covalently closed DNA becomes ATP-dependent. Exonucleolytic activity on either single- and double-stranded DNA was not detected. Taken together with the phenotypic properties of recD null mutants, it appears that the exonucleolytic activities of the RecBCD enzyme are not required for genetic recombination and the repair of either UV-induced photoproducts or mitomycin C-generated DNA cross-links, but are essential for the repair of methyl methanesulfonate-induced methylation.[1]References
- Biochemical and physical characterization of exonuclease V from Escherichia coli. Comparison of the catalytic activities of the RecBC and RecBCD enzymes. Palas, K.M., Kushner, S.R. J. Biol. Chem. (1990) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg
