HEMOLYTIC, BUT NOT CELL-INVASIVE ACTIVITY, OF ADENYLATE-CYCLASE TOXINIS SELECTIVELY AFFECTED BY DIFFERENTIAL FATTY-ACYLATION IN ESCHERICHIA-COLI

Adenylate cyclase toxin from Bordetella pertussis requires posttransla tional acylation of lysine 983 for the ability to deliver its catalyti c domain to the target cell interior and produce cyclic adenosine mono phosphate (cell-invasive activity) and to form transmembrane channels (hemolytic activity). When the toxin is expressed in Escherichia coli, it has reduced hemolytic activity, but comparable cell-invasive activ ity to that of adenylate cyclase toxin from B. pertussis. In contrast to the native protein from B. pertussis, which is exclusively palmitoy lated, recombinant toxin from E. coli is acylated at lysine 983 with a bout 87% palmitoylated and the remainder myristoylated. Furthermore, t he recombinant toxin contains an additional palmitoylation on approxim ately two-thirds of the lysines at position 860. These observations su ggest that the site and nature of posttranslational fatty-acylation ca n be dictated by the bacterial host used for expression and can have a significant, but selective, effect on protein function.