Bacteriophage mv4 Site-Specific Recombination: the Central Role of the P2 mv4Int-Binding Site

The contributions of the five mv4Int- and two mv4Xis arm-binding sites to the spatial intasome organization of bacteriophage mv4 were found not to be equivalent. The 8-bp overlap region was mapped to the left extremity of the core region and is directly flanked by the P2 Int arm-binding site. These results and the absence of characteristic Int core-binding sites suggest that the P2 site is the determinant for integrase positioning and recognition of the core region.