exbB

Summary

Gene Symbol: exbB
Description: membrane spanning protein in TonB-ExbB-ExbD complex
Alias: ECK2999, JW2974
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Ollis A, Kumar A, Postle K. The ExbD periplasmic domain contains distinct functional regions for two stages in TonB energization. J Bacteriol. 2012;194:3069-77 pubmed publisher
    ..Cytoplasmic membrane proteins ExbB and ExbD harness the proton gradient to energize TonB, which directly contacts and transmits this energy to ligand-..
  2. Braun V, Gaisser S, Herrmann C, Kampfenkel K, Killmann H, Traub I. Energy-coupled transport across the outer membrane of Escherichia coli: ExbB binds ExbD and TonB in vitro, and leucine 132 in the periplasmic region and aspartate 25 in the transmembrane region are important for ExbD activity. J Bacteriol. 1996;178:2836-45 pubmed
    ..membrane is transferred to the outer membrane with the aid of the Ton system, consisting of the proteins TonB, ExbB, and ExbD. In this paper we describe two point mutations which inactivate ExbD...
  3. Braun V. The structurally related exbB and tolQ genes are interchangeable in conferring tonB-dependent colicin, bacteriophage, and albomycin sensitivity. J Bacteriol. 1989;171:6387-90 pubmed
    Double exbB tolQ mutants of Escherichia coli were completely resistant to bacteriophages T1 and phi 80, in contrast to strains with exbB or tolQ mutations, which were sensitive...
  4. Held K, Postle K. ExbB and ExbD do not function independently in TonB-dependent energy transduction. J Bacteriol. 2002;184:5170-3 pubmed
    b>ExbB and ExbD proteins are part of the TonB-dependent energy transduction system and are encoded by the exb operon in Escherichia coli...
  5. Eick Helmerich K, Braun V. Import of biopolymers into Escherichia coli: nucleotide sequences of the exbB and exbD genes are homologous to those of the tolQ and tolR genes, respectively. J Bacteriol. 1989;171:5117-26 pubmed
    ..A 2.2-kilobase-pair DNA fragment of the exb locus was sequenced. It contained two open reading frames, designated exbB and exbD, which encoded polypeptides of 244 and 141 amino acids, respectively...
  6. Bulathsinghala C, Jana B, Baker K, Postle K. ExbB cytoplasmic loop deletions cause immediate, proton motive force-independent growth arrest. J Bacteriol. 2013;195:4580-91 pubmed publisher
    The Escherichia coli TonB system consists of the cytoplasmic membrane proteins TonB, ExbB, and ExbD and multiple outer membrane active transporters for diverse iron siderophores and vitamin B12...
  7. Karlsson M, Hannavy K, Higgins C. ExbB acts as a chaperone-like protein to stabilize TonB in the cytoplasm. Mol Microbiol. 1993;8:389-96 pubmed
    ..Two accessory proteins, ExbB and ExbD, are required for TonB function and it has been suggested that TonB and ExbBD form a complex in the ..
  8. Sverzhinsky A, Fabre L, Cottreau A, Biot Pelletier D, Khalil S, Bostina M, et al. Coordinated rearrangements between cytoplasmic and periplasmic domains of the membrane protein complex ExbB-ExbD of Escherichia coli. Structure. 2014;22:791-7 pubmed publisher
    Gram-negative bacteria rely on the ExbB-ExbD-TonB system for the import of essential nutrients...
  9. Brinkman K, Larsen R. Interactions of the energy transducer TonB with noncognate energy-harvesting complexes. J Bacteriol. 2008;190:421-7 pubmed
    ..the cognate energy-harvesting complex best services each transducer, components of the complexes (for TonB, ExbB and ExbD; for TolA, TolQ and TolR) are sufficiently similar that each complex can imperfectly replace the other...

More Information

Publications41

  1. Larsen R, Thomas M, Postle K. Protonmotive force, ExbB and ligand-bound FepA drive conformational changes in TonB. Mol Microbiol. 1999;31:1809-24 pubmed
    ..Previous studies of a TonB transmembrane domain mutant (TonB-delta V17) and its phenotypical suppressor (ExbB-A39E) suggested that TonB is conformationally sensitive...
  2. Kampfenkel K, Braun V. Topology of the ExbB protein in the cytoplasmic membrane of Escherichia coli. J Biol Chem. 1993;268:6050-7 pubmed
    The ExbB protein together with the ExbD and TonB proteins is involved in energy-coupled transport across the outer membrane of Escherichia coli...
  3. Skare J, Postle K. Evidence for a TonB-dependent energy transduction complex in Escherichia coli. Mol Microbiol. 1991;5:2883-90 pubmed
    ..Auxiliary proteins such as ExbB also play a role in TonB-dependent energy transduction...
  4. Pugsley A, Reeves P. Iron uptake in colicin B-resistant mutants of Escherichia coli K-12. J Bacteriol. 1976;126:1052-62 pubmed
    ..All four mutant classes (cbt, exbC, exbB, and tonB) were defective in the uptake of ferri-ennterochelin...
  5. Baker K, Postle K. Mutations in Escherichia coli ExbB transmembrane domains identify scaffolding and signal transduction functions and exclude participation in a proton pathway. J Bacteriol. 2013;195:2898-911 pubmed publisher
    ..Current data suggest that cytoplasmic membrane proteins ExbB and ExbD harness pmf energy...
  6. Celia H, Noinaj N, Zakharov S, Bordignon E, Botos I, Santamaria M, et al. Structural insight into the role of the Ton complex in energy transduction. Nature. 2016;538:60-65 pubmed publisher
    ..The Ton complex consists of TonB, ExbB, and ExbD, and uses the proton motive force at the inner membrane to transduce energy to the outer membrane via ..
  7. Larsen R, Postle K. Conserved residues Ser(16) and His(20) and their relative positioning are essential for TonB activity, cross-linking of TonB with ExbB, and the ability of TonB to respond to proton motive force. J Biol Chem. 2001;276:8111-7 pubmed
    ..The amino-terminal signal anchor of TonB and its interaction with the cytoplasmic membrane protein ExbB are essential to this process...
  8. Skare J, Ahmer B, Seachord C, Darveau R, Postle K. Energy transduction between membranes. TonB, a cytoplasmic membrane protein, can be chemically cross-linked in vivo to the outer membrane receptor FepA. J Biol Chem. 1993;268:16302-8 pubmed
    ..the outer membrane protease OmpT was shown to play a role in TonB turnover, both in the presence and absence of ExbB results in the rapid degradation of TonB...
  9. Karlsson M, Hannavy K, Higgins C. A sequence-specific function for the N-terminal signal-like sequence of the TonB protein. Mol Microbiol. 1993;8:379-88 pubmed
  10. Letain T, Postle K. TonB protein appears to transduce energy by shuttling between the cytoplasmic membrane and the outer membrane in Escherichia coli. Mol Microbiol. 1997;24:271-83 pubmed
    ..the cytoplasmic membrane and the outer membrane fractions, while two proteins with which it is known to interact, ExbB and ExbD, as well as the NADH oxidase activity characteristic of the cytoplasmic membrane, were localized in the ..
  11. Higgs P, Myers P, Postle K. Interactions in the TonB-dependent energy transduction complex: ExbB and ExbD form homomultimers. J Bacteriol. 1998;180:6031-8 pubmed
    The cytoplasmic membrane proteins ExbB and ExbD support TonB-dependent active transport of iron siderophores and vitamin B12 across the essentially unenergized outer membrane of Escherichia coli...
  12. Higgs P, Letain T, Merriam K, Burke N, Park H, Kang C, et al. TonB interacts with nonreceptor proteins in the outer membrane of Escherichia coli. J Bacteriol. 2002;184:1640-8 pubmed
    ..These results suggest that there may be multiple redundant sites where TonB can interact with the outer membrane prior to transducing energy to the outer membrane receptors. ..
  13. Sverzhinsky A, Chung J, Deme J, Fabre L, Levey K, Plesa M, et al. Membrane Protein Complex ExbB4-ExbD1-TonB1 from Escherichia coli Demonstrates Conformational Plasticity. J Bacteriol. 2015;197:1873-85 pubmed publisher
    ..powered by the proton motive force (PMF) of the cytoplasmic membrane (CM), harnessed by the CM-embedded complex of ExbB, ExbD, and TonB. Its stoichiometry, ensemble structural features, and mechanism of action are unknown...
  14. Braun V. Iron uptake by Escherichia coli. Front Biosci. 2003;8:s1409-21 pubmed
    ..provided by the proton motive force of the cytoplasmic membrane and transmitted to the outer membrane via the TonB-ExbB-ExbD proteins...
  15. Moeck G, Coulton J, Postle K. Cell envelope signaling in Escherichia coli. Ligand binding to the ferrichrome-iron receptor fhua promotes interaction with the energy-transducing protein TonB. J Biol Chem. 1997;272:28391-7 pubmed
    ..These studies demonstrate the significance of ligand binding at the external surface of the cell to mediate signal transduction across the outer membrane. ..
  16. Fischer E, Gunter 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;171:5127-34 pubmed
    The exb locus in Escherichia coli consists of two genes, termed exbB and exbD. Exb functions are related to TonB function in that most TonB-dependent processes are enhanced by Exb...
  17. Guterman S, Dann L. Excretion of enterochelin by exbA and exbB mutants of Escherichia coli. J Bacteriol. 1973;114:1225-30 pubmed
    ..These mutants are classified as exbA and exbB. The exbA mutants are chromium sensitive and require iron for growth, and the mutations are located in the tonB ..
  18. Pramanik A, Hauf W, Hoffmann J, Cernescu M, Brutschy B, Braun V. Oligomeric structure of ExbB and ExbB-ExbD isolated from Escherichia coli as revealed by LILBID mass spectrometry. Biochemistry. 2011;50:8950-6 pubmed publisher
    ..is derived from the proton-motive force of the cytoplasmic membrane, which is coupled to the outer membrane via the ExbB-ExbD-TonB protein complex...
  19. Ghosh J, Postle K. Disulphide trapping of an in vivo energy-dependent conformation of Escherichia coli TonB protein. Mol Microbiol. 2005;55:276-88 pubmed
    ..Cytoplasmic membrane proteins ExbB and ExbD appear to harvest pmf and transduce it to TonB...
  20. Vakharia Rao H, Kastead K, Savenkova M, Bulathsinghala C, Postle K. Deletion and substitution analysis of the Escherichia coli TonB Q160 region. J Bacteriol. 2007;189:4662-70 pubmed
    ..OM transporters and the potential energy of the cytoplasmic membrane (CM) proton gradient and CM proteins TonB, ExbB, and ExbD...
  21. Eick Helmerich K, Hantke K, Braun V. Cloning and expression of the exbB gene of Escherichia coli K-12. Mol Gen Genet. 1987;206:246-51 pubmed
    The exbB locus of Escherichia coli is involved in the uptake of certain iron(III) siderophore compounds, of vitamin B12 and of certain colicins...
  22. Braun V, Herrmann C. Evolutionary relationship of uptake systems for biopolymers in Escherichia coli: cross-complementation between the TonB-ExbB-ExbD and the TolA-TolQ-TolR proteins. Mol Microbiol. 1993;8:261-8 pubmed
    ..Group B colicins, ferric siderophores and vitamin B12 are taken up via the TonB-ExbB-ExbD, group A colicins via the TolA-TolQ-TolR system...
  23. Braun V. Energy-coupled transport and signal transduction through the gram-negative outer membrane via TonB-ExbB-ExbD-dependent receptor proteins. FEMS Microbiol Rev. 1995;16:295-307 pubmed
    ..Energy flows from the cytoplasmic into the outer membrane via a complex consisting of the TonB, ExbB and ExbD proteins which are anchored in the cytoplasmic membrane...
  24. Braun V, Braun M. Active transport of iron and siderophore antibiotics. Curr Opin Microbiol. 2002;5:194-201 pubmed
    ..complexes and in response to energy transfer from the cytoplasmic membrane into the outer membrane via the TonB-ExbB-ExbD protein complex...
  25. Clarke T, Tari L, Vogel H. Structural biology of bacterial iron uptake systems. Curr Top Med Chem. 2001;1:7-30 pubmed
    ..also shows that the proteins that provide energy for iron transport at the outer membrane, such as the TonB-ExbB-ExbD system, are structurally very similar across bacterial species...
  26. Braun V, Herrmann C. Point mutations in transmembrane helices 2 and 3 of ExbB and TolQ affect their activities in Escherichia coli K-12. J Bacteriol. 2004;186:4402-6 pubmed
    Replacement of glutamate 176, the only charged amino acid in the third transmembrane helix of ExbB, with alanine (E176A) abolished ExbB activity in all determined ExbB-dependent functions of Escherichia coli...
  27. Killmann H, Braun V. Energy-dependent receptor activities of Escherichia coli K-12: mutated TonB proteins alter FhuA receptor activities to phages T5, T1, phi 80 and to colicin M. FEMS Microbiol Lett. 1994;119:71-6 pubmed
    The activity of the FhuA receptor in the outer membrane of Escherichia coli is dependent on the TonB, ExbB and ExbD proteins which are anchored to the cytoplasmic membrane...
  28. Higgs P, Larsen R, Postle K. Quantification of known components of the Escherichia coli TonB energy transduction system: TonB, ExbB, ExbD and FepA. Mol Microbiol. 2002;44:271-81 pubmed
    ..enterochelin; TonB, the energy-transducing protein; and two cytoplasmic membrane proteins with less defined roles, ExbB and ExbD...
  29. Larsen R, Letain T, Postle K. In vivo evidence of TonB shuttling between the cytoplasmic and outer membrane in Escherichia coli. Mol Microbiol. 2003;49:211-8 pubmed
    ..in the cytoplasmic membrane, as determined by their abilities to cross-link to the cytoplasmic membrane protein ExbB and their abilities to respond conformationally to the presence or absence of proton motive force...
  30. Ollis A, Postle K. The same periplasmic ExbD residues mediate in vivo interactions between ExbD homodimers and ExbD-TonB heterodimers. J Bacteriol. 2011;193:6852-63 pubmed publisher
    ..In Escherichia coli, cytoplasmic membrane proteins ExbB and ExbD promote conformational changes in TonB, which transmits this energy to the transporters...
  31. Ahmer B, Thomas M, Larsen R, Postle K. Characterization of the exbBD operon of Escherichia coli and the role of ExbB and ExbD in TonB function and stability. J Bacteriol. 1995;177:4742-7 pubmed
    ..b>ExbB protein has been identified as an auxiliary protein in this process...
  32. Postle K. TonB system, in vivo assays and characterization. Methods Enzymol. 2007;422:245-69 pubmed
    ..TonB, ExbB, and ExbD are required to transduce the cytoplasmic membrane energy to these transporters. For E...