Membrane topology of MntB, the transmembrane protein component of an ABC transporter system for manganese in the cyanobacterium Synechocystis sp strain PCC 6803

The structure of the membrane protein MntB, a component of a manganese tran sporter system in Synechocystis sp. strain PCC 6803, was examined with a se ries of fusions to the reporter proteins alkaline phosphatase and beta-gala ctosidase. The results support a topological model for MntB consisting of n ine transmembrane segments, with the amino terminus of the protein being in the periplasm and the carboxyl terminus being in the cytoplasm.