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Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
Gene Review

fhuA  -  ferrichrome outer membrane transporter

Escherichia coli str. K-12 substr. MG1655

Synonyms: ECK0149, JW0146, T1, tonA
 
 
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Disease relevance of fhuA

 

High impact information on fhuA

  • Combination of the T1 or G72 mutation with mutations in the GGG.CCC sequence conserved in the anticodon stem of initiator tRNAs led to a further increase in the activities of these mutant tRNAs in elongation such that one of these mutants was now almost as good an elongator as E. coli elongator methionine tRNA [6].
  • Oligonucleotides were constructed and used not only as probes to map the gene on the T1 genome, but also as primers in sequencing reactions to establish the nucleotide sequence of the M.T1 locus by primer extension [7].
  • We then coupled this mutation to others which change the C1.A72 mismatch at the end of the acceptor stem to either a U1:A72 base pair (T1 mutant) or a C1:G72 base pair (G72 mutant) [8].
  • We employed a stopped-flow double-mixing technique to investigate the kinetics of the cis-->trans isomerization of this peptide bond in the unfolding and the trans-->cis isomerization in the refolding of Pro39Ala-ribonuclease T1 [9].
  • The tonA gene of Escherichia coli K12 was cloned into a multicopy plasmid, leading to substantial overproduction of the corresponding 78,000 Mr polypeptide in the outer membrane [10].
 

Chemical compound and disease context of fhuA

  • FhuA is a multifunctional protein in the outer membrane of Escherichia coli that actively transports [Fe3+]ferrichrome, the antibiotics albomycin and rifamycin CGP 4832, and mediates sensitivity of cells to the unrelated phages T5, T1, phi80 and UC-1, and to colicin M and microcin J25 [11].
  • Polymer-bound ferricrocin protected cells against colicin M and phage T5 by competition for the common tonA-coded outer membrane receptor protein [12].
  • Restriction analyses, DNA-DNA hybridization experiments, and guanine-plus-cytosine determinations demonstrated that UC-1 DNA was unrelated to that of other phages (T1, T5, and phi 80) which employ TonA as a receptor [13].
  • When this fusion gene was expressed in E. coli under the control of the trp promoter, active RNase T1 having the correct N-terminal sequence was secreted into the periplasmic space, indicating that the heterologous signal peptide had been cleaved off correctly [14].
 

Biological context of fhuA

  • The fhuA gene was cloned into pBR322, and the recombinant plasmid pGC01 was mutagenized by the insertion of 6-base-pair TAB (two amino acid Barany) linkers into CfoI and HpaII restriction sites distributed throughout the coding region [1].
  • A large deletion in fhuA was also isolated by TAB linker mutagenesis [1].
  • Finally, a strain carrying a mutant fhuA gene on the chromosome in which the linker insertion occurred after amino acid 82 showed a tonB phenotype [1].
  • For this purpose antibiotic resistance boxes flanked by symmetric polylinkers were inserted into fhuA and subsequently partially deleted [15].
  • The primary site for Fur binding spans 31 bp and contains two overlapping symmetry dyads which share the sequence 5'-TCATT-3'. It also contains extensive homology with a 19-bp consensus sequence for iron-regulated genes as deduced from comparison with the fhuA and fepA putative promoter sequences [16].
 

Anatomical context of fhuA

 

Associations of fhuA with chemical compounds

  • The rhizobial transformants expressing fhuA showed growth stimulation when co-inoculated with Ustilago maydis, a fungal species known to produce ferrichrome under iron starved conditions [3].
  • The iron supply by ferricrocin bound to polyethylene glycol was strictly dependent upon the functions expressed by the tonA and the tonB genes, as was the iron uptake promoted by free ferricrocin [12].
  • We conclude that the reversible preadsorption to the O8 and O9 polymannose antigens increases the rate of infection via the cellular receptor protein encoded by the fhuA (formerly tonA) gene [18].
  • The newly introduced cysteines and the replacement of the existing cysteines by serine did not alter sensitivity of cells to the FhuA ligands tested (T5, phi80, T1, colicin M, and albomycin) and fully supported growth on ferrichrome as the sole iron source [19].
  • Studies of the temperature dependence of the 1H, 13C, and 15N signals of the cysteinyl ligands to the [2Fe-2S] cluster show that the slope of the temperature dependence (delta delta/delta T-1) can be different for different atom types within a given residue [20].
 

Physical interactions of fhuA

  • These data suggest that the function controlled by the tonB gene is required for the translocation of colicin M from its initial binding site at the tonA-coded receptor protein to the target [21].
 

Other interactions of fhuA

  • Fusions between fhuA and phoA genes were constructed [22].
  • Phenotypic and mapping studies showed the mutations to be located in the fhuA, exb, tonB, and sbmA genes [23].
 

Analytical, diagnostic and therapeutic context of fhuA

  • The P. freudenreichii clone showed propionicin T1 activity in coculture, killing 90% of sensitive bacteria within 48 h [5].

References

  1. Insertion mutagenesis of the gene encoding the ferrichrome-iron receptor of Escherichia coli K-12. Carmel, G., Hellstern, D., Henning, D., Coulton, J.W. J. Bacteriol. (1990) [Pubmed]
  2. Identification of a new site for ferrichrome transport by comparison of the FhuA proteins of Escherichia coli, Salmonella paratyphi B, Salmonella typhimurium, and Pantoea agglomerans. Killmann, H., Herrmann, C., Wolff, H., Braun, V. J. Bacteriol. (1998) [Pubmed]
  3. Functional expression of Escherichia coli fhuA gene in Rhizobium spp. of Cajanus cajan provides growth advantage in presence of Fe(3+): ferrichrome as iron source. Rajendran, G., Mistry, S., Desai, A.J., Archana, G. Arch. Microbiol. (2007) [Pubmed]
  4. The beta-barrel domain of FhuADelta5-160 is sufficient for TonB-dependent FhuA activities of Escherichia coli. Braun, M., Killmann, H., Braun, V. Mol. Microbiol. (1999) [Pubmed]
  5. Heterologous production of antimicrobial peptides in Propionibacterium freudenreichii. Brede, D.A., Faye, T., Stierli, M.P., Dasen, G., Theiler, A., Nes, I.F., Meile, L., Holo, H. Appl. Environ. Microbiol. (2005) [Pubmed]
  6. Mutants of Escherichia coli formylmethionine tRNA: a single base change enables initiator tRNA to act as an elongator in vitro. Seong, B.L., RajBhandary, U.L. Proc. Natl. Acad. Sci. U.S.A. (1987) [Pubmed]
  7. Primary structure of a DNA (N6-adenine)-methyltransferase from Escherichia coli virus T1. DNA sequence, genomic organization, and comparative analysis. Schneider-Scherzer, E., Auer, B., de Groot, E.J., Schweiger, M. J. Biol. Chem. (1990) [Pubmed]
  8. Suppression of amber codons in vivo as evidence that mutants derived from Escherichia coli initiator tRNA can act at the step of elongation in protein synthesis. Seong, B.L., Lee, C.P., RajBhandary, U.L. J. Biol. Chem. (1989) [Pubmed]
  9. Non-prolyl cis-trans peptide bond isomerization as a rate-determining step in protein unfolding and refolding. Odefey, C., Mayr, L.M., Schmid, F.X. J. Mol. Biol. (1995) [Pubmed]
  10. Intermediates in the assembly of the TonA polypeptide into the outer membrane of Escherichia coli K12. Jackson, M.E., Pratt, J.M., Holland, I.B. J. Mol. Biol. (1986) [Pubmed]
  11. Diffusion through channel derivatives of the Escherichia coli FhuA transport protein. Braun, M., Killmann, H., Maier, E., Benz, R., Braun, V. Eur. J. Biochem. (2002) [Pubmed]
  12. Iron supply of Escherichia coli with polymer-bound ferricrocin. Coulton, J.W., Naegeli, H.U., Braun, V. Eur. J. Biochem. (1979) [Pubmed]
  13. UC-1, a new bacteriophage that uses the tonA polypeptide as its receptor. Lundrigan, M.D., Lancaster, J.H., Earhart, C.F. J. Virol. (1983) [Pubmed]
  14. Secretion of recombinant ribonuclease T1 into the periplasmic space of Escherichia coli with the aid of the signal peptide of alkaline phosphatase. Fujimura, T., Tanaka, T., Ohara, K., Morioka, H., Uesugi, S., Ikehara, M., Nishikawa, S. FEBS Lett. (1990) [Pubmed]
  15. Insertion derivatives containing segments of up to 16 amino acids identify surface- and periplasm-exposed regions of the FhuA outer membrane receptor of Escherichia coli K-12. Koebnik, R., Braun, V. J. Bacteriol. (1993) [Pubmed]
  16. Operator sequences of the aerobactin operon of plasmid ColV-K30 binding the ferric uptake regulation (fur) repressor. de Lorenzo, V., Wee, S., Herrero, M., Neilands, J.B. J. Bacteriol. (1987) [Pubmed]
  17. Involvement of inner and outer membrane components in the transport of iron and in colicin B action in Escherichia coli. Wookey, P., Rosenberg, H. J. Bacteriol. (1978) [Pubmed]
  18. Polymannose O-antigens of Escherichia coli, the binding sites for the reversible adsorption of bacteriophage T5+ via the L-shaped tail fibers. Heller, K., Braun, V. J. Virol. (1982) [Pubmed]
  19. Specific in vivo labeling of cell surface-exposed protein loops: reactive cysteines in the predicted gating loop mark a ferrichrome binding site and a ligand-induced conformational change of the Escherichia coli FhuA protein. Bös, C., Lorenzen, D., Braun, V. J. Bacteriol. (1998) [Pubmed]
  20. Protein expression, selective isotopic labeling, and analysis of hyperfine-shifted NMR signals of Anabaena 7120 vegetative [2Fe-2S]ferredoxin. Cheng, H., Westler, W.M., Xia, B., Oh, B.H., Markley, J.L. Arch. Biochem. Biophys. (1995) [Pubmed]
  21. Penetration of colicin M into cells of Escherichia coli. Braun, V., Frenz, J., Hantke, K., Schaller, K. J. Bacteriol. (1980) [Pubmed]
  22. Probing FhuA'-'PhoA fusion proteins for the study of FhuA export into the cell envelope of Escherichia coli K12. Günter, K., Braun, V. Mol. Gen. Genet. (1988) [Pubmed]
  23. The peptide antibiotic microcin 25 is imported through the TonB pathway and the SbmA protein. Salomón, R.A., Farías, R.N. J. Bacteriol. (1995) [Pubmed]
 
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