title: Characterization of the Streptococcus suis XerS recombinase and its unconventional cleavage of the difSL site.
abstract: XerC and XerD are members of the tyrosine recombinase family and mediate site-specific recombination that contributes to the stability of circular chromosomes in bacteria by resolving plasmid multimers and chromosome dimers to monomers prior to cell division. Homologues of xerC/xerD genes have been found in many bacteria, and in the lactococci and streptococci, a single recombinase called XerS can perform the functions of XerC and XerD. The xerS gene of Streptococcus suis was cloned, overexpressed and purified as a maltose-binding protein (MBP) fusion. The purified MBP-XerS fusion showed specific DNA-binding activity to both halves of the dif site of S. suis, and covalent protein-DNA complexes were also detected with dif site suicide substrates. These substrates were also cleaved in a specific fashion by MBP-XerS, generating cleavage products separated by an 11-bp spacer region, unlike the traditional 6-8-bp spacer observed in most tyrosine recombinases. Furthermore, xerS mutants of S. suis showed significant growth and morphological changes.
authors.affiliation: Département de microbiologie et immunologie, Université de Montréal, Montréal, QC, Canada.
authors.forename: Maxime
authors.initials: M
authors.lastname: Leroux
authors.forename: Fuli
authors.initials: F
authors.lastname: Jia
authors.forename: George
authors.initials: G
authors.lastname: Szatmari
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D045522:Recombinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic; D017011:Streptococcus suis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D045522:Recombinases