title: Topology of the phenylalanine-specific permease of Escherichia coli.
abstract: The PheP protein is a high-affinity phenylalanine-specific permease of the bacterium Escherichia coli. A topological model based on sequence analysis of the putative protein in which PheP has 12 transmembrane segments with both N and C termini located in the cytoplasm had been proposed (J. Pi, P. J. Wookey, and A. J. Pittard, J. Bacteriol. 173:3622-3629, 1991). This topological model of PheP has been further examined by generating protein fusions with alkaline phosphatase. Twenty-five sandwich fusion proteins have been constructed by inserting the 'phoA gene at specific sites within the pheP gene. In general, the PhoA activities of the fusions support a PheP topology model consisting of 12 transmembrane segments with the N and C termini in the cytoplasm. However, alterations to the model, affecting spans III and VI, were indicated by this analysis and were supported by additional site-directed mutagenesis of some of the residues involved.
authors.affiliation: Department of Microbiology, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Pi
authors.forename: A J
authors.initials: AJ
authors.lastname: Pittard
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D026921:Amino Acid Transport Systems, Neutral; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002462:Cell Membrane / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry
chemical_list: D026921:Amino Acid Transport Systems, Neutral; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D011993:Recombinant Fusion Proteins; C069320:phenylalanine-specific permease, E coli; D000469:Alkaline Phosphatase