FIG. 5.
TndX binding to its recombination sites. Purified TndX with a C-terminal His tag was used in gel shift assays to determine relative binding affinities to attL (A), attR (B), attTn (C), and attBCd (D) and the pseudo-attB site from B. subtilis, attBBs3 (E). In all panels, the white arrowhead indicates the position of the free probe and the black arrowhead is the position of the major TndX-probe complex. (A to D) Increasing concentrations of TndX were added to the binding reactions to generate final concentrations of 0, 0.28, 0.55, 0.83, and 1.1 μM (lanes 1 to 5, respectively). Lane 6 contains the same binding reaction as does lane 5 except that 10-fold more unlabeled probe was added as a specific competitor. (E) The concentration of TndX added to each binding reaction was 0.17, 0.34, 0.68, and 1.35 μM (lanes 1 to 5, respectively).