Fig 3.

CodY interaction with the ilvE promoter is enhanced in the presence of isoleucine. Radiolabeled DNA probes were incubated with 1,500 nM purified recombinant DnaK (control) or CodY. Branched-chain amino acids added were isoleucine (I), leucine (L), and valine (V), individually or in combination (ILV), to a final concentration of 3 mM (each). Promoter regions used for binding assays were the ATPase promoter (lanes 1 and 2) and the ilvE promoter (lanes 3 to 9). Arrows at left indicate migration of free probes (FP).