Interactions of the site-specific recombinases XerC and XerD with the recombination site dif.
The Xer site-specific recombination system of Escherichia coli is involved in the stable inheritance of circular replicons. Multimeric replicons, produced by homologous recombination, are converted to monomers by the action of two related recombinases XerC and XerD. Site-specific recombination at a locus, dif, within the chromosomal replication terminus region is thought to convert dimeric chromosomes to monomers, which can then be segregated prior to cell division. The recombinases XerC and XerD bind cooperatively to dif, where they catalyse recombination. Chemical modification of specific bases and the phosphate-sugar backbone within dif was used to investigate the requirements for binding of the recombinases. Site-directed mutagenesis was then used to alter bases implicated in recombinase binding. Characterization of these mutants by in vitro recombinase binding and in vivo recombination, has demonstrated that the cooperative interactions between XerC and XerD can partially overcome DNA alterations that should interfere with specific recombinase-dif interactions.
Department of Biochemistry, University of Oxford, UK.
G W
GW
Blakely
D J
DJ
Sherratt
D000478:Alkylation; D001483:Base Sequence; D001665:Binding Sites; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D019426:Integrases; D008745:Methylation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D011196:Potassium Permanganate; D045522:Recombinases; D011995:Recombination, Genetic
D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D045522:Recombinases; C473360:XerC protein, E coli; D011196:Potassium Permanganate; D004254:DNA Nucleotidyltransferases; D019426:Integrases; C473361:XerD protein, E coli; C115006:integron integrase IntI1