Two-component signal transduction systems enable bacteria to sense, respond, and adapt
to a wide range of environments, stressors, and growth conditions. In the prototypical two-
component system, a sensor histidine kinase catalyzes its autophosphorylation and then
subseqeuntly transfers the phosphoryl group to a response regulator, which can then effect
changes in cellular physiology, often by regulating gene expression. The utility of these
signaling systems is underscored by their prevalence throughout the bacterial kingdom and …