Structure-function relationships in the Bvg and Evg two-component phosphorelay systems

The unorthodox two-component phosphorelay systems BvgAS and EvgAS of Bordet ella pertussis and E. coli, respectively, are suitable model systems to inv estigate the molecular basis of signalling specificity, because, despite th eir high relatedness on the sequence level, they do nor cross-talk to each other. We could show that the two systems belong to the obligate type of ph osphorelay systems and that signalling specificity is mediated by the HPt m odules of the histidine kinases and the receiver domains of the effector pr oteins. To gain more insight into signalling specificity on the molecular l evel, we started a detailed structural analysis of the respective proteins using a combination of genetic and biochemical methods including limited pr oteolysis and chemical modification of purified proteins and their mass spe ctrometrical analysis.