[Preliminary characterization of a new system allowing maltose assimilation by Escherichia coli]

We showed that Klebsiella pneumoniae and Erwinia herbicola possessed a pathway for maltose metabolism which could function in parallel with that encoded by the classical maltose regulon. Indeed, specific DNA fragments isolated from these two bacteria allowed growth on maltose of any of the mal mutants of Escherichia coli when in a multicopy number. The preliminary characterization of the E. herbicola DNA fragment indicated that a 4-Kb region was sufficient to complement the mal mutations of E. coli, and that this region encoded at least one 50-Kd protein. This protein is probably bound to the cytoplasmic membrane and its synthesis is induced by maltose independently of malT, the positive regulator gene of the maltose regulon.