Immunological relatedness between Bordetella pertussis and rat brain adenylyl cyclases

A prokaryotic adenylyl cyclase, secreted by Bordetella pertussis, shares a common functional property with eukaryotic adenylyl cyclases, i.e., regulation by the eukaryotic protein calmodulin. Making use of polyclonal antibodies raised against the bacterial adenylyl cyclase and the rat brain adenylyl cyclase catalytic component, respectively, we showed an immunological cross-reactivity between the two enzymes. Furthermore, B. pertussis adenylyl cyclase was inhibited and immunoprecipitated by the homologous and one of the heterologous immune sera. These results suggest an evolutionary relationship between the B. pertussis enzyme and its eukaryotic counterpart.