Characterizing Response Regulator Activation by MALS

All organisms have molecular mechanisms in place to sense and respond to environmental changes. Bacteria use two-component signal transduction pathways, which comprise a histidine kinase (HK) and a response regulator protein (RR). Extracellular stimuli sensed by the HK induce an autophosphorylation reaction at a histidine residue of the enzyme that is subsequently transferred to a specific aspartate residue at the receiver domain of a cognate RR. Upon phosphorylation, the output domain of the RR is activated, leading to changes in gene expression, protein-protein interactions or enzymatic activities. This application note demonstrates the characterization of the oligomeric transitions between inactive and active states of two RRs (R1 and R10), which are phosphorylated by the same HK.