Calmodulin activates prokaryotic adenylate cyclase.

Abstract
The adenylate cyclase of Bordetella pertussis is stimulated 100- to 1000-fold in a dose-dependent manner by calf brain calmodulin. The system has the following properties. The activation is prevented by ethylene glycol bis(.beta.-aminoethyl ether)-N,N,N'',N''-tetraacetic acid and restored by Ca2+. Oxidation of the methionine residues of calmodulin abolishes the ability to activate the cyclase. Trifluoperazine inhibits calmodulin-activated cyclase. A troponin C preparation stimulates the B. pertussis cyclase with < 0.01 the potency of calmodulin. Although calmodulin was not demonstrated in prokaryotes, this is an example of a (eukaryotic) calmodulin effect in a prokaryote.