Fig. 2.

Full-length and truncated forms of rHrcA differ in their binding affinity for the CIRCE operator. (A) Silver stains of 12% SDS-PAGE showing purified wild-type chlamydial rHrcA (lane 1) utilized in previous studies (51–53), and full-length (lane 2) and truncated forms (lane 3) of recombinant HrcA used for in vitro assays in this report. (B) Recombinant forms of full-length and truncated HrcA that had been purified by metal affinity chromatography were bound to CIRCE DNA affinity beads in the presence of 100 mM NaCl. The beads were then sequentially washed with increasing concentrations of NaCl over a range from 150 to 800 mM NaCl. Wash fractions were resolved by 12% SDS-PAGE, and proteins were visualized by silver staining. IN, input sample.