The structures of Edema Factor alone and Edema Factor bound to calmodulin
without substrate has been crystallized and its structure determined by
x-ray crystallography. Based upon these crystal structures, a method
assaying for inhibitors of infection by a bacteria is presented which
comprises obtaining a potential inhibitor, obtaining a calmodulin
activated adenylyl cyclase exotoxin, obtaining calmodulin, admixing the
potential inhibitor, the exotoxin, and the calmodulin, and assaying to
determine whether or not the potential inhibitor inhibits production of
cAMP by exotoxin.