title: Two related recombinases are required for site-specific recombination at dif and cer in E. coli K12.
abstract: The stable inheritance of ColE1-related plasmids and the normal partition of the E. coli chromosome require the function of the Xer site-specific recombination system. We show that in addition to the XerC recombinase, whose function has already been implicated in this system, a second chromosomally encoded recombinase, XerD, is required. The XerC and XerD proteins show 37% identity and bind to separate halves of the recombination site. Both proteins act catalytically in the recombination reaction. Recombination site asymmetry and the requirement of two recombinases ensure that only correctly aligned sites are recombined. We predict that normal partition of most circular chromosomes requires the participation of site-specific recombination to convert any multimers (arising by homologous recombination) to monomers.
authors.affiliation: Institute of Genetics, University of Glasgow, Scotland.
authors.forename: G
authors.initials: G
authors.lastname: Blakely
authors.forename: G
authors.initials: G
authors.lastname: May
authors.forename: R
authors.initials: R
authors.lastname: McCulloch
authors.forename: L K
authors.initials: LK
authors.lastname: Arciszewska
authors.forename: M
authors.initials: M
authors.lastname: Burke
authors.forename: S T
authors.initials: ST
authors.lastname: Lovett
authors.forename: D J
authors.initials: DJ
authors.lastname: Sherratt
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004254:DNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D019426:Integrases; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D045522:Recombinases; D011995:Recombination, Genetic / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: 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