title: Direct interaction of aminopeptidase A with recombination site DNA in Xer site-specific recombination.
abstract: Xer site-specific recombination at ColE1 cer converts plasmid multimers into monomers, thus ensuring the heritable stability of ColE1. Two related recombinase proteins, XerC and XerD, catalyse the strand exchange reaction at a 30 bp recombination core site. In addition, two accessory proteins, PepA and ArgR, are required for recombination at cer. These two accessory proteins are thought to act at 180 bp of accessory sequences adjacent to the cer recombination core to ensure that recombination only occurs between directly repeated sites on the same molecule. Here, we demonstrate that PepA and ArgR interact directly with cer, forming a complex in which the accessory sequences of two cer sites are interwrapped approximately three times in a right-handed fashion. We present a model for this synaptic complex, and propose that strand exchange can only occur after the formation of this complex.
authors.affiliation: Microbiology Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
authors.forename: C
authors.initials: C
authors.lastname: Alén
authors.forename: D J
authors.initials: DJ
authors.lastname: Sherratt
authors.forename: S D
authors.initials: SD
authors.lastname: Colloms
mesh_terms: D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D003087:Colicins / Q000235:genetics; D018983:DNA Footprinting; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism*; D043384:Glutamyl Aminopeptidase; D019426:Integrases; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009698:Nucleoproteins / Q000378:metabolism; D011485:Protein Binding; D045522:Recombinases; D011995:Recombination, Genetic; D012097:Repressor Proteins / Q000378:metabolism*
chemical_list: C087018:ArgR protein, Bacteria; D001426:Bacterial Proteins; D003087:Colicins; D004269:DNA, Bacterial; D009698:Nucleoproteins; D045522:Recombinases; D012097:Repressor Proteins; D004254:DNA Nucleotidyltransferases; D019426:Integrases; C115006:integron integrase IntI1; D000626:Aminopeptidases; D043384:Glutamyl Aminopeptidase