Abstract
Previously we proposed a transmembrane model of the FhuA receptor protein in the outer membrane of Escherichia coli. Removal of the largest loop at the cell surface converted the FhuA transport protein into an open channel and rendered cells resistant to the FhuA-specific phages T1, T5, and phi 80 and to colicin M. In the present study we employed acetylated hexapeptide amides covering the entire surface loop to investigate binding of the phages and of colicin M. Competitive peptide mapping proved to be a powerful technique to uncover three ligand binding sites within a region of 34 amino acid residues. Hexapeptides derived from three specific regions of the surface loop inhibited infection of cells by the phages and killing by colicin M. Two of these regions were common among all four FhuA ligands. Electron microscopy of phage T5 revealed that one inhibitory peptide triggered a strong conformational change leading to the release of DNA from the phage head. These results suggest that the FhuA gating loop is the target for specific binding of phages T1, T5, and phi 80 and colicin M.
Full Text
The Full Text of this article is available as a PDF (458.5 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bradbeer C. The proton motive force drives the outer membrane transport of cobalamin in Escherichia coli. J Bacteriol. 1993 May;175(10):3146–3150. doi: 10.1128/jb.175.10.3146-3150.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Braun V., Killmann H., Benz R. Energy-coupled transport through the outer membrane of Escherichia coli small deletions in the gating loop convert the FhuA transport protein into a diffusion channel. FEBS Lett. 1994 Jun 6;346(1):59–64. doi: 10.1016/0014-5793(94)00431-5. [DOI] [PubMed] [Google Scholar]
- Crawford J. T., Goldberg E. B. The function of tail fibers in triggering baseplate expansion of bacteriophage T4. J Mol Biol. 1980 Jun 5;139(4):679–690. doi: 10.1016/0022-2836(80)90054-6. [DOI] [PubMed] [Google Scholar]
- Fischer E., Günter K., Braun V. Involvement of ExbB and TonB in transport across the outer membrane of Escherichia coli: phenotypic complementation of exb mutants by overexpressed tonB and physical stabilization of TonB by ExbB. J Bacteriol. 1989 Sep;171(9):5127–5134. doi: 10.1128/jb.171.9.5127-5134.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hancock R. W., Braun V. Nature of the energy requirement for the irreversible adsorption of bacteriophages T1 and phi80 to Escherichia coli. J Bacteriol. 1976 Feb;125(2):409–415. doi: 10.1128/jb.125.2.409-415.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heller K. J., Schwarz H. Irreversible binding to the receptor of bacteriophages T5 and BF23 does not occur with the tip of the tail. J Bacteriol. 1985 May;162(2):621–625. doi: 10.1128/jb.162.2.621-625.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heller K., Braun V. Accelerated adsorption of bacteriophage T5 to Escherichia coli F, resulting from reversible tail fiber-lipopolysaccharide binding. J Bacteriol. 1979 Jul;139(1):32–38. doi: 10.1128/jb.139.1.32-38.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heller K., Braun V. Polymannose O-antigens of Escherichia coli, the binding sites for the reversible adsorption of bacteriophage T5+ via the L-shaped tail fibers. J Virol. 1982 Jan;41(1):222–227. doi: 10.1128/jvi.41.1.222-227.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hoffmann H., Fischer E., Kraut H., Braun V. Preparation of the FhuA (TonA) receptor protein from cell envelopes of an overproducing strain of Escherichia coli K-12. J Bacteriol. 1986 May;166(2):404–411. doi: 10.1128/jb.166.2.404-411.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Killmann H., Benz R., Braun V. Conversion of the FhuA transport protein into a diffusion channel through the outer membrane of Escherichia coli. EMBO J. 1993 Aug;12(8):3007–3016. doi: 10.1002/j.1460-2075.1993.tb05969.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Killmann H., Braun V. An aspartate deletion mutation defines a binding site of the multifunctional FhuA outer membrane receptor of Escherichia coli K-12. J Bacteriol. 1992 Jun;174(11):3479–3486. doi: 10.1128/jb.174.11.3479-3486.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koebnik R., Braun V. 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. J Bacteriol. 1993 Feb;175(3):826–839. doi: 10.1128/jb.175.3.826-839.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Krauel V., Heller K. J. Cloning, sequencing, and recombinational analysis with bacteriophage BF23 of the bacteriophage T5 oad gene encoding the receptor-binding protein. J Bacteriol. 1991 Feb;173(3):1287–1297. doi: 10.1128/jb.173.3.1287-1297.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moeck G. S., Bazzaz B. S., Gras M. F., Ravi T. S., Ratcliffe M. J., Coulton J. W. Genetic insertion and exposure of a reporter epitope in the ferrichrome-iron receptor of Escherichia coli K-12. J Bacteriol. 1994 Jul;176(14):4250–4259. doi: 10.1128/jb.176.14.4250-4259.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Saigo K. Isolation of high-density mutants and identification of nonessential structural proteins in bacteriophage T5; dispensability of L-shaped tail fibers and a secondary major head protein. Virology. 1978 Apr;85(2):422–433. doi: 10.1016/0042-6822(78)90449-x. [DOI] [PubMed] [Google Scholar]
- WEIDEL W., KELLENBERGER E. The E. coli B-receptor for the phage T5. II. Electron microscopic studies. Biochim Biophys Acta. 1955 May;17(1):1–9. doi: 10.1016/0006-3002(55)90314-0. [DOI] [PubMed] [Google Scholar]