FIG. 6.

Binding of CI and ς^A-RNAP to their cognate binding sites. The α-³²P-labeled 183-bp DNA segment (81 pM) was incubated with CI (6 nM) (lane 2) and increasing concentrations of ς^A-RNAP (13, 17.5, 22, 26.5, 34, and 44 nM) (lanes 3 to 8) or with 22 nM of ς^A-RNAP and increasing CI concentrations (2.7, 5.6, 11, and 22 nM). The unbound probe (Free), the CI-DNA complexes (I and II), ς^A-RNAP–DNA (RPI and RPII), and the ternary complex CI–ς^A-RNAP–DNA (II* and CI-RP) are indicated. Lane 1, unbound DNA probe.