Figure 5.

In vitro cleavage of the Xer recombination sites. The substrate double-stranded oligonucleotides include a phosphorothioate analog (underlined, red dot) to trap the DNA-Xer product formed after digestion and covalent attachment to the Y residue of the recombinase (top). Reactions were carried out at 37 °C for 1 h in the presence or absence of XerC_Ab (brown) and XerD_Ab (green). Samples were heated at 95 °C for 5 min and subjected to 1% sodium dodecyl sulfate–8% polyacrylamide gel electrophoresis. The asterisk represents the 5′-end biotinylation. The bands were visualized as described in Materials and Methods.