Figure 5. Complete trajectory-scanning mutagenesis of EnvZ and OmpR.

Each histidine kinase, indicated on the far right, was autophosphorylated and tested for phosphotransfer to each of the response regulators listed across the top. Mutants of EnvZ are named according to the identity of the three specificity residues being examined; for instance, wild-type EnvZ is ‘TLA’ whereas the mutant T250V is ‘VLA’. Mutants of OmpR are named similarly. All phosphotransfer reactions were incubated for 10 seconds with the exception of RstB and CpxA, which were examined at both 10 seconds and 1 minute. Each kinase profile was composed of two separate gels that were run, exposed to phosphor screens, and scanned in parallel. The resulting two gel images were treated identically and then stitched together between OmpR(EVAPFN) and OmpR(EVATTP).