FIG. 2.

(a) Comparison of the DNA-binding sites (bs) recognized by RhaS, RhaR, and AraC. Horizontal arrows indicate the half-sites and their relative orientations. Notice that the downstream half-sites are all in the same relative orientation whereas the upstream half-sites are not. Bracketed bases are conserved in the RhaS and RhaR DNA-binding sites. The outer and inner major grooves of the RhaS binding site are indicated. The −35 regions of the promoters are shown. Vertical arrows indicate amino acid-base pair contacts between AraC H-T-H 1 and its DNA-binding site. (b) Sequence of amino acids 246 to 255 of RhaS, showing high similarity with the aligned region of RhaR (amino acids 282 to 291). Solid lines indicate identical amino acids; broken lines represent similar amino acids.