Abstract
The study of iron uptake promoted by 2,3-dihydroxybenzoate (DHB) into Escherichia coli K-12 aroB mutants allowed some dissection of outer and cytoplasmic membrane functions. These strains are unable to produce the iron-transporting chelate enterochelin, unless fed with a precursor such as DHB. When added to the medium, enterochelin and its natural breakdown products, the linear dimer and trimer of 2,3-dihydroxybenzoylserine (DBS), efficiently transported iron via the feuB, tonB and fep gene products. Thus mutants in these genes were defective in transport of the above chelates. However, feuB and tonB mutants were able to take up iron when DHB was added to the medium. Thus DHB-promoted iron uptake bypassed two functions required for the transport of ferric-enterochelin from the medium. One of these functions, feuB, has been shown to be an outer membrane protein. In contrast to three other iron transport systems including ferric-enterochelin uptake, DHB-promoted iron uptake was little affected by the uncoupler 2,4-dinitrophenol. Dissipation of the energized state of the cytoplasmic membrane apparently only affects those iron transport systems which require an outer membrane protein. Since DHB-promoted iron uptake bypasses the feuB outer membrane protein and the tonB function, it is concluded that, in ferricenterochelin transport, the tonB gene may function in coupling the energized state of the cytoplasmic membrane to the protein-dependent outer membrane permeability. DHB-promoted iron uptake required the synthesis and enzymatic breakdown of enterochelin as judged by the effects of the entF and fesB mutations. A fep mutant was not only deficient in the transport of the ferric chelates of enterochelin and its breakdown products, but was also deficient in DHB-promoted iron uptake. A scheme is presented in which iron diffuses as DHB-complex through the outer membrane, and is subsequently captured by enterochelin or DBS dimer or trimer and translocated across the cytoplasmic membrane.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Abbreviations
- DHB:
-
2,3-dihydroxybenzoate
- DBS:
-
2,3-dihydroxybenzoylserine
- NTA:
-
nitrilotriacetate
- DNP:
-
2,4-dinitrophenol
References
Bachmann, B. J., Low, K. B., Taylor, A. L.: Recalibrated linkage map of Escherichia coli K-12. Bacteriol. Rev. 40, 116–167 (1976)
Bassford, P. J., Bradbeer, C., Kadner, R. J., Schnaitman, C. A.: Transport of vitamin B12 in tonB mutants of Escherichia coli. J. Bacteriol 128, 242–247 (1976)
Berger, E. A.: Different mechanisms of energy coupling for the active transport of proline and glutamine in Escherichia coli. Proc. Natl. Acad. Sci. U.S.A. 70, 1514–1518 (1973)
Berger, E. A., Heppel, L. A.: Different mechanisms of energy coupling for the shock-sensitive and shock-resistant permeases of Escherichia coli. J. Biol. Chem. 249, 7747–7755 (1974)
Bradbeer, C., Woodrow, M. L.: Transport of vitamin B12 in Escherichia coli: Energy dependence. J. Bacteriol. 128, 99–104 (1976)
Braun, V., Hancock, R. E. W., Hantke, K., Hartmann, A.: Functional organization of the outer membrane of Escherichia coli. Phage and colicin receptors as components of iron uptake systems. J. Supramol. Struct. 5, 37–38 (1976)
Bryce, G. F., Brot, N.: Studies on the enzymatic synthesis of the cyclic trimer of 2,3-dihydroxy-N-benzoyl-l-serine in Escherichia coli. Biochemistry 11, 1708–1715 (1972)
Cardelli, J., Konisky, J.: Isolation and characteristics of an Escherichia coli mutant tolerant to colicins Ia and Ib. J. Bacteriol. 119, 379–385 (1974)
Cleland, W. W.: Steady State Kinetics. In: The enzyme, Vol. II (P. D. Boyer, ed.), pp. 1–66, New York: Academic Press 1970
Cox, G. B., Gibson, H., Luke, R. K. J., Newton, N. A., O'Brien, I. G., Rosenberg, H.: Mutations affecting iron transport in Escherichia coli. J. Bacteriol. 104, 219–226 (1970)
Cunarro, J., Weiner, M. W.: Mechanism of action of agents which uncouple oxidative phosphorylation: direct correlation between proton-carrying and respiratory-releasing properties using rat liver mitochondria. Biochim. Biophys. Acta 387, 234–240 (1975)
Davies, J. K., Reeves, P.: Genetics of resistance of colicins in Escherichia coli K-12: Cross resistance among colicins of group B. J. Bacteriol. 123, 96–101 (1975)
Decad, G. M., Nikaido, H. Outer membrane of gram-negative bacteria. XII. Molecular-sieving function of cell wall. J. Bacteriol. 128, 325–336 (1976)
Frost, G. E., Rosenberg, H.: The citrate-dependent iron transport system in Escherichia coli K-12 Biochim. Biophys. Acta 330, 90–101 (1973)
Frost, G. E., Rosenberg, H.: Relationship between the tonB locus and iron transport in Escherichia coli. J. Bacteriol 124, 704–712 (1975)
Guterman, S. K.: Colicin B: mode of action and inhibition by enterochelin. J. Bacteriol. 114, 1217–1224 (1973)
Hancock, R. E. W., Braun, V.: The colicin I receptor of Escherichia coli K-12 has a role in enterochelin-mediated iron transport. FEBS Lett. 65, 208–210 (1976a)
Hancock, R. E. W., Braun, V.: Nature of the energy requirement for the irreversible adsorption of bacteriophages T1 and Φ80 to Escherichia coli K-12. J. Bacteriol. 125, 409–415 (1976b)
Hancock, R. E. W. Hantke, K., Braun, V.: Iron transport in Escherichia coli K-12: Involvement of the colicin B receptor and of a citrate-inducible protein. J. Bacteriol. 127, 1370–1375 (1976)
Hantke, K., Braun, V.: Membrane receptor dependent iron transport in Escherichia coli. FEBS Lett. 49, 301–305 (1975a)
Hantke, K., Braun, V.: A function common to iron-enterochelin transport and the action of colicins B, I, V in Escherichia coli. FEBS Lett. 59, 277–281 (1975b)
Ito, T., Neilands, J. B.: Products of “low iron fermentation” with Bacillus subtilis: Isolation, characterization and synthesis of 2,3-dihydroxybenzoylglycine. J. Amer. Chem. Soc. 80, 4645–4646 (1958)
Klein, W. L., Boyer, P. D.: Energization of active transport in Escherichia coli. J. Biol. Chem. 247, 7257–7265 (1972)
Langman, L., Young, I. G., Frost, G. E., Rosenberg, H., Gibson, F.: Enterochelin system of iron transport in Escherichia coli: Mutations affecting ferric-enterochelin esterase. J. Bacteriol. 112, 1142–1149 (1972)
Luke, R. K. J., Gibson, F.: Location of three genes concerned with the conversion of 2,3-dihydroxybenzoate into enterochelin in Escherichia coli K-12. J. Bacteriol. 107, 557–562 (1971)
O'Brien, I.G., Cox, G. B., Gibson, F.: Enterochelin hydrolysis and iron metabolism in Escherichia coli. Biochim. Biophys. Acta 237, 537–549 (1971)
O'Brien, I. G., Gibson, F.: The structure of enterochelin and related 2,3-dihydroxyl-N-benzoylserine conjugates from Escherichia coli Biochim. Biophys Acta 215, 393–402 (1970)
Pittard, J., Wallace, B. J.: Distribution and function of genes concerned with aromatic biosynthesis in Escherichia coli. J. Bacteriol. 91, 1494–1508 (1966)
Pugsley, A. P., Reeves, P.: Iron uptake in colicin B-resistant mutants of Escherichia coli K-12. J. Bacteriol. 126, 1052–1062 (1976a)
Pugsley, A. P., Reeves, P.: Characterization of colicin B resistant mutants of Escherichia coli K-12: colicin resistance and the role of enterochelin. J. Bacteriol. 127, 218–228 (1976b)
Pugsley, A. P., Reeves, P.: The role of colicin receptors in the uptake of enterochelin by Escherichia coli K-12. Biochem. Biophys. Res. Commun. 74, 903–911 (1977a)
Pugsley, A. P., Reeves, P.: Uptake of ferrienterochelin by Escherichia coli: energy dependent stage of uptake. J. Bacteriol. 130, 26–36 (1977b)
Rogers, G. D., Neilands, J. B.: Microbial iron transport compounds. In: Handbook of microbiology, Vol. 2 (A. L. Laskin, H. A. Lechevalier, eds.), pp. 823–830. Cleveland: C.R.C. Press 1974
Rosenberg, H., Young, I. G.: Iron transport in the enteric bacteria. In: Microbial iron metabolism (J. B. Neilands, ed.) pp. 67–82 New York: Academic Press 1974
Wang, C. C., Newton, A.: Iron transport in Escherichia coli: relationship between chromium sensitivity and high iron requirement in mutants of Escherichia coli. J. Bacteriol 98, 1135–1141 (1969)
Wang, C. C., Newton, A.: An additional step in the transport of iron defined by the tonB locus of Escherichia coli. J. Biol. Chem. 246, 2147–2151 (1971)
Wayne, R., Frick, K. Neilands, J. B.: Siderophore protection against colicins M, B, V, and Ia in Escherichia coli. J. Bacteriol. 126, 7–12 (1976)
Wayne, R., Neilands, J. B.: Evidence for common binding sites for ferrichrome compounds and bacteriophage Φ80 in the cell envelope of Escherichia coli. J. Bacteriol. 121, 497–503 (1975)
Young, I. G.: Preparation of enterochelin from Escherichia coli. Preparative Biochem. 6, 123–131 (1976)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hancock, R.E.W., Hantke, K. & Braun, V. Iron transport in Escherichia coli K-12. Arch. Microbiol. 114, 231–239 (1977). https://doi.org/10.1007/BF00446867
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00446867