title: Nucleotide sequence and genetic organization of the ferric enterobactin transport system: homology to other periplasmic binding protein-dependent systems in Escherichia coli.
abstract: The nucleotide sequence of the Escherichia coli fep genomic region has been determined. Three new loci were identified. One of these, P43, encodes a membrane protein that is not essential for ferric enterobactin transport. Two others, fepD and fepG, were found to be essential for transport and their translational products showed extensive homology to other integral membrane proteins involved in TonB-dependent transport processes. The FepC amino acid sequence suggested a peripheral membrane location and revealed conserved ATP-binding domains. Together these data indicate that ferric enterobactin is transported through a typical periplasmic binding protein-dependent system. In addition, the transcriptional organization of these genes was examined and primer extension analysis identified a single iron-regulated bidirectional promoter between the P43 gene and the fepDGC operon.
authors.affiliation: Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia 65212.
authors.forename: C M
authors.initials: CM
authors.lastname: Shea
authors.forename: M A
authors.initials: MA
authors.lastname: McIntosh
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D001692:Biological Transport / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D004252:DNA Mutational Analysis; D004758:Enterobactin / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D007501:Iron / Q000378:metabolism*; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics; D011956:Receptors, Cell Surface; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D011956:Receptors, Cell Surface; C029489:enterobactin receptor; D004758:Enterobactin; D007501:Iron