Villion Manuela, Szatmari George
Département de microbiologie et immunologie, Université de Montréal, CP 6128, Succ. Centre-Ville, H3C 3J7, Montreal, QC, Canada.
FEMS Microbiol Lett. 2003 Sep 12;226(1):65-71. doi: 10.1016/S0378-1097(03)00577-9.
XerC and XerD are two site-specific recombinases, which act on different sites to maintain replicons in a monomeric state. This system, which was first discovered and studied in Escherichia coli, is present in several species including Proteus mirabilis, where the XerD recombinase was previously characterized by our laboratory. In this paper, we report the presence of the xerC gene in P. mirabilis. Using in vitro reactions, we show that the two P. mirabilis recombinases display binding and cleavage activity on the E. coli dif site and the ColE1 cer site, together or in collaboration with E. coli recombinases. In vivo, P. mirabilis XerC and XerD are able to resolve and monomerize a plasmid containing two cer sites, increasing its stability. However, P. mirabilis XerC, in combination with E. coli XerD, is unable to perform these functions.
XerC和XerD是两种位点特异性重组酶，它们作用于不同位点以维持复制子处于单体状态。该系统最初是在大肠杆菌中发现和研究的，存在于包括奇异变形杆菌在内的多个物种中，我们实验室之前已对奇异变形杆菌中的XerD重组酶进行了表征。在本文中，我们报道了奇异变形杆菌中xerC基因的存在。通过体外反应，我们表明奇异变形杆菌的这两种重组酶在大肠杆菌的dif位点和ColE1的cer位点上单独或与大肠杆菌重组酶协同显示出结合和切割活性。在体内，奇异变形杆菌的XerC和XerD能够拆分并使含有两个cer位点的质粒单体化，从而提高其稳定性。然而，奇异变形杆菌的XerC与大肠杆菌的XerD组合则无法执行这些功能。
