Altered recognition mutants of the response regulator PhoB: A new genetic strategy for studying protein-protein interactions

摘要

Two-component regulatory systems require highly specific interactions between histidine kinase (trans- itter) and response regulator (receiver) proteins. We have developed a novel genetic strategy that is based on tightly regulated synthesis of a given protein to identify domains and residues of an interacting protein that are critical for inter- ctions between them. Using a reporter strain synthesizing the nonpartner kinase VanS under tight arabinose control and carrying a promoter-lacZ fusion activated by phospho-PhoB, we isolated altered recognition (AR) mutants of PhoB showing enhanced activation (phosphorylation) by VanS as arabinose- dependent Lac~+ mutants.