FIGURE 6.

Determination of the effect of regacin on the DNA binding activity of RegA and TyrR by EMSA. A, a ³²P-labeled 233-bp DNA fragment containing the regulatory region of kfc was mixed with 200 nm MBP::RegA and 45 mm NaHCO₃ in the absence or presence of varying concentrations of regacin. B, a ³²P-labeled 157-bp DNA fragment containing the regulatory region of mtr was mixed with 200 nm TyrR, 50 μm ATP, and 100 μm tyrosine in the absence or presence of varying concentrations of regacin. After incubation at 30 °C for 20 min, the samples were separated by electrophoresis on a native polyacrylamide gel. Lane 1, DNA fragment alone (control); lanes 2–5, DNA fragment mixed with 200 nm MBP::RegA (panel A) or TyrR (panel B) in the presence of 0, 5, 10, and 30 μm regacin, respectively. Free DNA (F) and the protein-DNA complex (P) are indicated.