Xer site-specific recombination. DNA strand rejoining by recombinase XerC.
Xer site-specific recombination functions in the stable maintenance of circular replicons in Escherichia coli. Each of two related recombinase proteins, XerC and XerD, cleaves a specific pair of DNA strands, exchanges them, and rejoins them to the partner DNA molecule during a complete recombination reaction. The rejoining activity of recombinase XerC has been analyzed using isolated covalent XerC-DNA complexes resulting from DNA cleavage reactions upon Holliday junction substrates. These covalent protein-DNA complexes are competent in the rejoining reaction, demonstrating that covalently bound XerC can catalyze strand rejoining in the absence of other proteins. This contrasts with a recombinase-mediated cleavage reaction, which requires the presence of both recombinases, the recombinase mediating catalysis at any given time requiring activation by the partner recombinase. In a recombining nucleoprotein complex, both cleavage and rejoining can occur prior to dissociation of the complex.
Grainge
I
I
Division of Molecular Genetics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
Sherratt
D J
DJ
D001483:Base Sequence; D004254:DNA Nucleotidyltransferases / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D019426:Integrases; D008969:Molecular Sequence Data; D045522:Recombinases; D011995:Recombination, Genetic
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D045522:Recombinases; C473360:XerC protein, E coli; D004254:DNA Nucleotidyltransferases; D019426:Integrases; C473361:XerD protein, E coli; C115006:integron integrase IntI1