FIG. 4.

DNA binding of XisR23A and XisR26A. The final concentration of wild-type Xis was 0.1 μM, and that of the mutant Xis proteins was 5 μM. Each reaction contained 2.5 nM labeled DNA and 50 ng of sonicated calf thymus DNA. Where indicated, 6.3 ng of FIS was present. Electrophoresis was performed at 4°C.