Colloms S D, Alén C, Sherratt D J
Department of Biochemistry, University of Oxford, UK.
Mol Microbiol. 1998 May;28(3):521-30. doi: 10.1046/j.1365-2958.1998.00812.x.
Two recombinases, XerC and XerD, act at the recombination sites psi and cer in plasmids pSC101 and Co1E1 respectively. Recombination at these sites maintains the plasmids in a monomeric state and helps to promote stable plasmid inheritance. The accessory protein PepA acts at both psi and cer to ensure that only intramolecular recombination takes place. An additional accessory protein, ArgR, is required for recombination at cer but not at psi. Here, we demonstrate that the ArcA/ArcB two-component regulatory system of Escherichia coli, which mediates adaptation to anaerobic growth conditions, is required for efficient recombination in vivo at psi. Phosphorylated ArcA binds to psi in vitro and increases the efficiency of recombination at this site. Binding of ArcA to psi may contribute to the formation of a higher order synaptic complex between a pair of psi sites, thus helping to ensure that recombination is intramolecular.
两种重组酶，XerC和XerD，分别作用于质粒pSC101中的psi位点和质粒Co1E1中的cer位点。这些位点的重组可使质粒保持单体状态，并有助于促进质粒的稳定遗传。辅助蛋白PepA作用于psi和cer位点，以确保只发生分子内重组。另一种辅助蛋白ArgR是cer位点重组所必需的，但psi位点重组不需要。在此，我们证明了大肠杆菌的ArcA/ArcB双组分调节系统（介导对厌氧生长条件的适应）是体内psi位点高效重组所必需的。磷酸化的ArcA在体外与psi位点结合，并提高该位点的重组效率。ArcA与psi位点的结合可能有助于在一对psi位点之间形成更高阶的突触复合体，从而有助于确保重组是分子内的。
