Identification and localization of the membrane-associated, ATP-binding subunit of the oligopeptide permease of Salmonella typhimurium

The OppF protein, a component of the oligopeptide permease of Salmonella typhimurium, is an ATP-binding protein and is believed to couple ATP hydrolysis to the transport process. This protein is an example of a large family of closely related proteins which couple ATP to a variety of different biological processes. The oppF gene has been cloned and sequenced. In order to identify and characterize its protein product we overproduced the protein from the cloned gene. Anti-OppF antibodies were raised against a synthetic peptide. Using these antibodies as a probe we identified OppF in wild-type and overproducing strains. Protease accessibility studies showed the protein to be a peripheral membrane protein located on the cytoplasmic side of the inner membrane. These findings have general implications for the organization and function of this class of prokaryotic and eukaryotic transport system.