FIG. 7.

Charge distribution within the HAMP domains of TlpB and Tsr. HAMP domains are cytoplasmic linker regions found in bacterial chemoreceptors. The HAMP sequence of Tsr senses changes in cytoplasmic pH (32). By convention, basic amino acids are given a “+” charge and acidic amino acids are given a “−” charge. The HAMP domains were identified as indicated in the text for TlpB from H. pylori strains KE26695 and J99 and a Tlp ortholog (Hmus) of H. mustelae. Tsr is the serine-sensing chemoreceptor of the E. coli K12 strain.