Bordetella pertussis adenylate cyclase toxin as a tool to analyze molecular interactions in a bacterial two-hybrid system

Bordetella pertussis secretes a calmodulin-activated adenylate cyclase toxi n (CyaA) that is able to enter into eukaryotic cells. We took advantage of the modular structure of the catalytic domain of CyaA to design a genetic s ystem that can detect protein-protein interactions in Escherichia coli. Thi s bacterial two-hybrid system is based on the functional complementation be tween two complementary fragments, T25 and T18, of the catalytic domain of CyaA, in an E. coli cya strain. This bacterial two-hybrid system could find applications in the studies of structure/function relationships of protein s, in functional analysis of genomes, in high-throughput screening of inter acting ligands and in design of new therapeutic agents.