title: Regulation of Sin recombinase by accessory proteins.
abstract: Sin recombinase from Staphylococcus aureus acts selectively on directly repeated resH sites, assembling an intertwined synapse in which exactly three supercoils are trapped between the points of strand exchange. Resolution requires the two Sin binding sites in resH (site I, where strand exchange occurs, and site II) and a non-specific DNA-bending protein (e.g. Hbsu). We show that a single amino acid substitution in Sin (I100T) is sufficient to relax the normal requirements for site II and Hbsu. Using this hyperactive protein, and the variant recombination site resH(AT), we investigate the roles of site II and Hbsu in synapsis and strand exchange. We conclude that Sin bound at site II, and Hbsu, act together to control site I alignment and the topology of the synapse, and to stimulate strand exchange.
authors.affiliation: University of Glasgow, Institute of Biomedical and Life Sciences, Division of Molecular Genetics, Anderson College, 56 Dumbarton Road, Glasgow G11 6NU, UK. sr2q@udcf.gla.ac.uk
authors.forename: Sally J
authors.initials: SJ
authors.lastname: Rowland
authors.forename: Martin R
authors.initials: MR
authors.lastname: Boocock
authors.forename: W Marshall
authors.initials: WM
authors.lastname: Stark
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D001665:Binding Sites; D004254:DNA Nucleotidyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry; D004270:DNA, Circular / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000502:physiology*; D011995:Recombination, Genetic; D013211:Staphylococcus aureus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004270:DNA, Circular; D004268:DNA-Binding Proteins; C075779:Hbsu protein, bacteria; D004254:DNA Nucleotidyltransferases; C086893:sin protein, Staphylococcus aureus