Summary
The transport of Fe3+ into cells of Escherichia coli occurs via siderophores and the uptake through the outer membrane of three Fe3+-siderophore compounds containing hydroxamate residues requires three specific receptor proteins. In contrast, transport through the cytoplasmic membrane is catalysed by three common proteins encoded by the fhuB, fhuC and fhuD genes. The nucleotide sequence of a DNA fragment containing the fhuC and fhuD genes has been determined: the open reading frame of fhuC contains 795 nucleotides which encode a polypeptide with a molecular weight of 29 255 and the largest open reading frame of the fhuD region comprises 888 nucleotides. However, we propose that translation of fhuD initiates at the fourth potential start codon resulting in a polypeptide with a molecular weight of 28 282. Both proteins are moderately nonpolar and membrane-bound. They lack obvious signal sequences. Segments of the FhuC protein display strong homology to ATP-binding proteins, suggesting a function in Fe3+ uptake similar to the ATP-binding proteins of transport systems that depend on periplasmic proteins. This study completes the nucleotide sequence of the fhu operon which consists of the four genes fhuA fhuC fhuD fhuB arranged in this order on the E. coli chromosome and transcribed from fhuA to fhuB.
Similar content being viewed by others
References
Ames GFL (1986) Bacterial periplasmic transport systems: structure, mechanism, and evolution. Annu Rev Biochem 55:397–425
Biggin MD, Gibson TJ, Hong GF (1983) Buffer-gradient gels and 35S-label as an aid to rapid DNA sequence determination. Proc Natl Acad Sci USA 80:3963–3965
Bradbeer C, Kenley JS, DiMasi DR, Leighton M (1978) Transport of vitamin B12 in Escherichia coli. Corrinoid specificities of the periplasmic B12-binding protein and of eneergy-dependent B12 transport. J Biol Chem 253:1347–1352
Braun V (1985a) The unusual features of the iron transport systems of Escherichia coli. Trends Biochem Sci 10:75–78
Braun V (1985b) The iron transport systems of Escherichia coli. In: Martonosi AN (ed) The enzymes of biological membranes, vol 3. Plenum Press, New York, pp 617–652
Braun V, Schaller U, Wolff H (1973) A common receptor protein for phage T5 and colicin M in the outer membrane of Escherichia coli. Biochim Biophys Acta 328:87–97
Broome-Smith JK, Edelman A, Yousif S, Spratt B (1985) The nucleotide sequences of the ponA and ponB genes encoding penicilin-binding proteins 1A and 1B of Escherichia coli K12. Eur J Biochem 147:437–446
Coulton JW, Mason P, Cameron DR, Carmel G, Jean R, Rode HN (1986) Protein fusions of β-galactosidase to the ferrichrome-iron receptor of Escherichia coli K-12. J Bacteriol 165:181–192
Doolittle RF, Johnson MS, Husain I, van Houten B, Thomas DC, Sancar A (1986) Domainal evolution of a prokaryotic DNA repair protein and its relationship to active-transport proteins. Nature 323:451–452
Duncan TM, Parasonage D, Senior AE (1986) Structure of the nucleotide binding domain in the β-subunit of Escherichia coli F1-ATPase. FEBS Lett 208:1–6
Fecker L, Braun V (1983) Cloning and expression of the fhu genes involved in the iron (III)-hydroxamate uptake of Escherichia coli. J Bacteriol 156:1301–1314
Friedrich MJ, DeVeau LC, Kadner RJ (1986) Nucleotide sequence of the btuCED genes involved in vitamin B12 transport in Escherichia coli and homology with components of periplasmic-binding-protein-dependent transport systems. J Bacteriol 167:928–934
Hantke K, Braun V (1985) Membrane receptor-dependent iron transport in Escherichia coli. FEBS Lett 49:301–305
Higgins C, Hiles ID, Salmond GP, Gill DR, Downie JA, Evans LJ, Holland IB, Gray L, Buckel CD, Bell AW, Hermodson MA (1986) A family of related ATP binding subunits coupled to many distinct biological processes in bacteria. Nature 323:448–450
Hoffmann H, Fischer E, Kraut H, Braun V (1986) Preparation of the FhuA (TonA) receptor protein from cell envelopes of an overproducing strain of Escherichia coli K12. J Bacteriol 166:404–411
Köster W, Braun V (1986) Iron hydroxamate transport of Escherichia coli: nucleotide sequence of the fhuB gene and identification of the protein. Mol Gen Genet 204:435–442
Looman AC, Bodlaender J, de Gruyter M, Vogelaar A, van Knippenberg PH (1986) Secondary structure as primary determinant of the efficiency of ribosomal binding sites in Escherichia coli. Nucleic Acids Res 14:5481–5497
Lucky M, Wayne R, Neilands JB (1975) In vitro competition between ferrichrome and phage for the outer membrane T5 receptor complex of Escherichia coli. Biochem Biophys Res Commun 64:687–693
Kyte J, Doolittle RF (1982) A simple method for displaying the hydrophobic character of a protein. J Mol Biol 157:105–132
Maniatis T, Fritsch EF, Sambrock J (1981) Molecular cloning —A laboratory manual. Cold Spring Harbor Laboratory, Cold Spring Harbor New York
Messing J, Crea R, Seeburg P (1981) A system for shotgun DNA-sequencing. Nucleic Acids Res 9:309–321
Raymond KN, Müller G, Matzanke BF (1984) Complexation of iron by siderophores. A review of their solution and structural chemistry and biological function. Top Curr Chem 123:49–102
Sanger F, Nicklen S, Coulson AR (1977) DNA sequencing with chain terminating inhibitors. Proc Natl Acad Sci USA 74:5463–5467
Shine J, Dalgarno L (1974) Determinants of cistron specificity in bacterial ribosomes. Nature 254:34–38
Tabor S, Richardson CC (1985) A bacteriophage T7 RNA polymerase/promoter system for controlled exclusive expression of specific genes. Proc Natl Acad Sci USA 82:1074–1078
Author information
Authors and Affiliations
Additional information
Communicated by J. Lengeler
Rights and permissions
About this article
Cite this article
Burkhardt, R., Braun, V. Nucleotide sequence of the fhuC and fhuD genes involved in iron (III) hydroxamate transport: Domains in FhuC homologous to ATP-binding proteins. Mol Gen Genet 209, 49–55 (1987). https://doi.org/10.1007/BF00329835
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00329835