title: Point mutations in two conserved glycine residues within the integral membrane protein FhuB affect iron(III) hydroxamate transport.
abstract: A region of substantial homology, comprising 32 amino acids around a highly conserved glycine residue, is located near the C-terminal ends of the hydrophobic Fhu, Fec, Fep, Fat, and Btu transport proteins involved in the uptake of ferrisiderophores and vitamin B12 into Escherichia coli and Vibrio anguillarum. Furthermore, a region similar in location and sequence containing an invariant glycine at an equivalent position was identified in the hydrophobic component of all other periplasmic binding protein-dependent (PBT) systems. In the FhuB protein, which is twice the size of the other PBT-related inner membrane proteins and which displays an internal homology, two conserved glycine residues are present. Alteration of Gly at positions 226 and 559 to Ala, Val, or Glu reduced iron(III) hydroxamate uptake, suggesting that this homologous region may play a general role in the mechanism of PBT-dependent transport.
authors.affiliation: Mikrobiologie II, Universität Tübingen, FRG.
authors.forename: W
authors.initials: W
authors.lastname: Köster
authors.forename: B
authors.initials: B
authors.lastname: Böhm
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005290:Ferric Compounds / Q000378:metabolism*; D005291:Ferrichrome / Q000031:analogs & derivatives / Q000494:pharmacology; D005838:Genotype; D005998:Glycine; D006877:Hydroxamic Acids / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D033902:Periplasmic Binding Proteins; D010957:Plasmids; D015183:Restriction Mapping
chemical_list: D000900:Anti-Bacterial Agents; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D005290:Ferric Compounds; D006877:Hydroxamic Acids; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D009838:Oligodeoxyribonucleotides; D033902:Periplasmic Binding Proteins; C074579:iron (III) hydroxamate; C069968:fhuB protein, E coli; D005291:Ferrichrome; C015657:albomycin; D005998:Glycine