Gene Symbol: acrB
Description: multidrug efflux system protein
Alias: ECK0456, JW0451, acrE
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Tikhonova E, Zgurskaya H. AcrA, AcrB, and TolC of Escherichia coli Form a Stable Intermembrane Multidrug Efflux Complex. J Biol Chem. 2004;279:32116-24 pubmed
    ..when the affinity tag is attached to either of the proteins suggesting bi-partite interactions between AcrA, AcrB, and TolC. We show that antibiotics, the substrates of AcrAB-TolC, stabilize interactions within the complex...
  2. Murakami S. Multidrug efflux transporter, AcrB--the pumping mechanism. Curr Opin Struct Biol. 2008;18:459-65 pubmed publisher
    ..They pump a wide range of antibiotics out of the cell by proton motive force. AcrB is the major RND transporter in Escherichia coli...
  3. Seeger M, Schiefner A, Eicher T, Verrey F, Diederichs K, Pos K. Structural asymmetry of AcrB trimer suggests a peristaltic pump mechanism. Science. 2006;313:1295-8 pubmed
    The AcrA/AcrB/TolC complex spans the inner and outer membranes of Escherichia coli and serves as its major drug-resistance pump...
  4. Murakami S, Nakashima R, Yamashita E, Yamaguchi A. Crystal structure of bacterial multidrug efflux transporter AcrB. Nature. 2002;419:587-93 pubmed
    b>AcrB is a major multidrug exporter in Escherichia coli. It cooperates with a membrane fusion protein, AcrA, and an outer membrane channel, TolC. We have determined the crystal structure of AcrB at 3.5 A resolution...
  5. Gerken H, Misra R. Genetic evidence for functional interactions between TolC and AcrA proteins of a major antibiotic efflux pump of Escherichia coli. Mol Microbiol. 2004;54:620-31 pubmed
    Genetic data have suggested that TolC, AcrA and AcrB constitute a major antibiotic efflux system in Escherichia coli...
  6. Lu W, Zhong M, Wei Y. Folding of AcrB Subunit Precedes Trimerization. J Mol Biol. 2011;411:264-74 pubmed publisher
    b>AcrB and its homologues are major players in the efflux of anti-microbials out of Gram-negative bacteria. The structural and functional unit of AcrB is a homo-trimer...
  7. Zgurskaya H, Nikaido H. Bypassing the periplasm: reconstitution of the AcrAB multidrug efflux pump of Escherichia coli. Proc Natl Acad Sci U S A. 1999;96:7190-5 pubmed
    ..We have purified the cytoplasmic membrane component, AcrB, to near homogeneity, and reconstituted the protein into proteoliposomes...
  8. Bleuel C, Grosse C, Taudte N, Scherer J, Wesenberg D, Krauss G, et al. TolC is involved in enterobactin efflux across the outer membrane of Escherichia coli. J Bacteriol. 2005;187:6701-7 pubmed
    ..tunnel protein TolC but none of the respective seven resistance nodulation cell division (RND) proteins CusA, AcrB, AcrD, AcrF, MdtF (YhiV), or the twin RND MdtBC (YegNO) was essential for enterobactin export across the outer ..
  9. Yu E, Aires J, McDermott G, Nikaido H. A periplasmic drug-binding site of the AcrB multidrug efflux pump: a crystallographic and site-directed mutagenesis study. J Bacteriol. 2005;187:6804-15 pubmed
    The Escherichia coli AcrB multidrug efflux pump is a membrane protein that recognizes many structurally dissimilar toxic compounds...

More Information


  1. Sennhauser G, Amstutz P, Briand C, Storchenegger O, Grutter M. Drug export pathway of multidrug exporter AcrB revealed by DARPin inhibitors. PLoS Biol. 2007;5:e7 pubmed
    The multidrug exporter AcrB is the inner membrane component of the AcrAB-TolC drug efflux system in Escherichia coli and is responsible for the resistance of this organism to a wide range of drugs...
  2. Murakami S, Nakashima R, Yamashita E, Matsumoto T, Yamaguchi A. Crystal structures of a multidrug transporter reveal a functionally rotating mechanism. Nature. 2006;443:173-9 pubmed
    b>AcrB is a principal multidrug efflux transporter in Escherichia coli that cooperates with an outer-membrane channel, TolC, and a membrane-fusion protein, AcrA. Here we describe crystal structures of AcrB with and without substrates...
  3. Murakami S, Tamura N, Saito A, Hirata T, Yamaguchi A. Extramembrane central pore of multidrug exporter AcrB in Escherichia coli plays an important role in drug transport. J Biol Chem. 2004;279:3743-8 pubmed
    We previously reported the crystal structure of the major multidrug exporter AcrB in Escherichia coli (Murakami, S., Nakashima, R., Yamashita, E., and Yamaguchi, A. (2002) Nature 419, 587-593)...
  4. Tal N, Schuldiner S. A coordinated network of transporters with overlapping specificities provides a robust survival strategy. Proc Natl Acad Sci U S A. 2009;106:9051-6 pubmed publisher
    ..This strategy also confers evolvability to the organism by reducing constraints on change and allowing the accumulation of nonlethal variation. ..
  5. Rosenberg E, Bertenthal D, Nilles M, Bertrand K, Nikaido H. Bile salts and fatty acids induce the expression of Escherichia coli AcrAB multidrug efflux pump through their interaction with Rob regulatory protein. Mol Microbiol. 2003;48:1609-19 pubmed
    ..Thus, it is likely that E. coli is protecting itself by the Rob-mediated upregulation of AcrAB against the harmful effects of bile salts and fatty acids in the intestinal tract. ..
  6. Symmons M, Bokma E, Koronakis E, Hughes C, Koronakis V. The assembled structure of a complete tripartite bacterial multidrug efflux pump. Proc Natl Acad Sci U S A. 2009;106:7173-8 pubmed publisher
    ..structure enabled in vivo cross-linking to map intermolecular contacts between the adaptor AcrA and the transporter AcrB, defining a periplasmic interface between several transporter subdomains and the contiguous beta-roll, beta-barrel, ..
  7. Seeger M, von Ballmoos C, Eicher T, Brandstätter L, Verrey F, Diederichs K, et al. Engineered disulfide bonds support the functional rotation mechanism of multidrug efflux pump AcrB. Nat Struct Mol Biol. 2008;15:199-205 pubmed publisher
    The AcrA-AcrB-TolC complex is the major multidrug efflux pump in Escherichia coli. The asymmetric structure of the trimeric inner-membrane component AcrB implies functional rotation of the monomers and a peristaltic mode of drug efflux...
  8. Thanassi D, Cheng L, Nikaido H. Active efflux of bile salts by Escherichia coli. J Bacteriol. 1997;179:2512-8 pubmed
    ..It followed saturation kinetics with Vmax and Km values in the neighborhood of 0.3 nmol min(-1) mg of protein(-1) and 50 microM, respectively. ..
  9. Ruiz C, Levy S. Regulation of acrAB expression by cellular metabolites in Escherichia coli. J Antimicrob Chemother. 2014;69:390-9 pubmed publisher
    ..Deletion of the acrB gene increased the expression of the acrAB operon...
  10. Yu E, McDermott G, Zgurskaya H, Nikaido H, Koshland D. Structural basis of multiple drug-binding capacity of the AcrB multidrug efflux pump. Science. 2003;300:976-80 pubmed
    ..We obtained x-ray crystallographic structures of the trimeric AcrB pump from Escherichia coli with four structurally diverse ligands...
  11. Nikaido H, Zgurskaya H. AcrAB and related multidrug efflux pumps of Escherichia coli. J Mol Microbiol Biotechnol. 2001;3:215-8 pubmed
    The AcrAB system of Escherichia coli is a multidrug efflux system composed of an RND-type transporter AcrB and a periplasmic accessory protein AcrA, and pumps out a wide variety of lipophilic and amphiphilic inhibitors directly into the ..
  12. Eicher T, Brandstätter L, Pos K. Structural and functional aspects of the multidrug efflux pump AcrB. Biol Chem. 2009;390:693-9 pubmed publisher
    The tripartite efflux system AcrA/AcrB/TolC is the main pump in Escherichia coli for the efflux of multiple antibiotics, dyes, bile salts and detergents...
  13. Törnroth Horsefield S, Gourdon P, Horsefield R, Brive L, Yamamoto N, Mori H, et al. Crystal structure of AcrB in complex with a single transmembrane subunit reveals another twist. Structure. 2007;15:1663-73 pubmed
    ..In Escherichia coli, the AcrB:AcrA:TolC efflux complex forms a principal transporter for which structures of the individual component proteins ..
  14. Nagano K, Nikaido H. Kinetic behavior of the major multidrug efflux pump AcrB of Escherichia coli. Proc Natl Acad Sci U S A. 2009;106:5854-8 pubmed publisher
    ..Here we use intact cells of Escherichia coli containing the intact multiprotein complex AcrB-AcrA-TolC, and measure the kinetic constants for various cephalosporins, by assessing the periplasmic concentration ..
  15. Seeger M, Diederichs K, Eicher T, Brandstätter L, Schiefner A, Verrey F, et al. The AcrB efflux pump: conformational cycling and peristalsis lead to multidrug resistance. Curr Drug Targets. 2008;9:729-49 pubmed
    ..In E. coli, the tripartite efflux system AcrA/AcrB/TolC is the pump in charge of the efflux of multiple antibiotics, dyes, bile salts and detergents...
  16. Husain F, Humbard M, Misra R. Interaction between the TolC and AcrA proteins of a multidrug efflux system of Escherichia coli. J Bacteriol. 2004;186:8533-6 pubmed
    ..AcrA was independent of the presence of any externally added substrate of the efflux pump or of the pump protein, AcrB. The biochemical demonstration of a TolC-AcrA interaction is consistent with genetic studies in which extragenic ..
  17. Okusu H, Ma D, Nikaido H. AcrAB efflux pump plays a major role in the antibiotic resistance phenotype of Escherichia coli multiple-antibiotic-resistance (Mar) mutants. J Bacteriol. 1996;178:306-8 pubmed
    ..This experiment identified the AcrAB system as the major pump responsible for making the Mar mutants resistant to many agents, including tetracycline, chloramphenicol, ampicillin, nalidixic acid, and rifampin. ..
  18. Drew D, Klepsch M, Newstead S, Flaig R, de Gier J, Iwata S, et al. The structure of the efflux pump AcrB in complex with bile acid. Mol Membr Biol. 2008;25:677-82 pubmed publisher
    ..Bile acid removal in E. coli is thought to be mediated primarily by the multidrug efflux pump, AcrB. Here, we present the structure of E. coli AcrB in complex with deoxycholate at 3.85 A resolution...
  19. Touze T, Eswaran J, Bokma E, Koronakis E, Hughes C, Koronakis V. Interactions underlying assembly of the Escherichia coli AcrAB-TolC multidrug efflux system. Mol Microbiol. 2004;53:697-706 pubmed
    ..Using in vivo cross-linking, we show for the first time that the antiporter AcrB and the adaptor AcrA, which form a translocase in the inner membrane, interact with the outer membrane TolC exit ..
  20. Schulz R, Vargiu A, Collu F, Kleinekathöfer U, Ruggerone P. Functional rotation of the transporter AcrB: insights into drug extrusion from simulations. PLoS Comput Biol. 2010;6:e1000806 pubmed publisher
    ..Its active part, the homotrimeric transporter AcrB, is responsible for the selective binding of substrates and energy transduction...
  21. Viveiros M, Jesus A, Brito M, Leandro C, Martins M, Ordway D, et al. Inducement and reversal of tetracycline resistance in Escherichia coli K-12 and expression of proton gradient-dependent multidrug efflux pump genes. Antimicrob Agents Chemother. 2005;49:3578-82 pubmed
    ..All transporter genes were overexpressed after induced resistance with acrF being 80-fold more expressed in the DeltaacrAB tetracycline-induced strain. ..
  22. Fralick J. Evidence that TolC is required for functioning of the Mar/AcrAB efflux pump of Escherichia coli. J Bacteriol. 1996;178:5803-5 pubmed
    ..These results are compatible with the hypothesis that TolC is a component of the AcrAB efflux complex. ..
  23. Bohnert J, Schuster S, Seeger M, Fähnrich E, Pos K, Kern W. Site-directed mutagenesis reveals putative substrate binding residues in the Escherichia coli RND efflux pump AcrB. J Bacteriol. 2008;190:8225-9 pubmed publisher
    The Escherichia coli multidrug efflux pump protein AcrB has recently been cocrystallized with various substrates, suggesting that there is a phenylalanine-rich binding site around F178 and F615...
  24. Takatsuka Y, Nikaido H. Covalently linked trimer of the AcrB multidrug efflux pump provides support for the functional rotating mechanism. J Bacteriol. 2009;191:1729-37 pubmed publisher
    Escherichia coli AcrB is a proton motive force-dependent multidrug efflux transporter that recognizes multiple toxic chemicals having diverse structures...
  25. Nikaido H, Takatsuka Y. Mechanisms of RND multidrug efflux pumps. Biochim Biophys Acta. 2009;1794:769-81 pubmed publisher
    ..a sizable hydrophobic domain; however, this may simply be a reflection of the nature of the binding site within AcrB. Genetic studies of chimeric transporters showed that much of the substrate specificity is determined by their ..
  26. Chollet R, Chevalier J, Bryskier A, Pages J. The AcrAB-TolC pump is involved in macrolide resistance but not in telithromycin efflux in Enterobacter aerogenes and Escherichia coli. Antimicrob Agents Chemother. 2004;48:3621-4 pubmed
    ..aerogenes acrAB or tolC derivatives compared to that in the parental strain. Two independent efflux pumps, inhibited by phenylalanine arginine beta-naphthylamide, expel macrolides and telithromycin in E. aerogenes...
  27. Psakis G, Polaczek J, Essen L. AcrB et al.: Obstinate contaminants in a picogram scale. One more bottleneck in the membrane protein structure pipeline. J Struct Biol. 2009;166:107-11 pubmed publisher
    ..45% of the purified proteins were contaminated with what was later identified as the multidrug efflux pump (AcrB)of E. coli, and 17% with the succinate dehydrogenase...
  28. Lee H, Bernstein H. The targeting pathway of Escherichia coli presecretory and integral membrane proteins is specified by the hydrophobicity of the targeting signal. Proc Natl Acad Sci U S A. 2001;98:3471-6 pubmed
    ..Replacement of the MBP or OmpA signal peptide with the first transmembrane segment of AcrB abolished the dependence on SecB for transport and rerouted both proteins into the SRP targeting pathway...
  29. Pos K. Drug transport mechanism of the AcrB efflux pump. Biochim Biophys Acta. 2009;1794:782-93 pubmed publisher
    ..In E. coli, the tripartite efflux system AcrA/AcrB/TolC is the pump that extrudes multiple antibiotics, dyes, bile salts and detergents...
  30. Ye C, Wang Z, Lu W, Wei Y. Unfolding study of a trimeric membrane protein AcrB. Protein Sci. 2014;23:897-905 pubmed publisher
    The folding of a multi-domain trimeric ?-helical membrane protein, Escherichia coli inner membrane protein AcrB, was investigated. AcrB contains both a transmembrane domain and a large periplasmic domain...
  31. Kawarai T, Ogihara H, Furukawa S, Aono R, Kishima M, Inagi Y, et al. High hydrostatic pressure treatment impairs AcrAB-TolC pump resulting in differential loss of deoxycholate tolerance in Escherichia coli. J Biosci Bioeng. 2005;100:613-6 pubmed
    ..coli cells. ..
  32. Lu C, Bentley W, Rao G. Comparisons of oxidative stress response genes in aerobic Escherichia coli fermentations. Biotechnol Bioeng. 2003;83:864-70 pubmed
    ..These results also suggest that different molecular responses occur under different aeration schemes, all of which are intended to combat oxidative damage. ..
  33. Elkins C, Nikaido H. Chimeric analysis of AcrA function reveals the importance of its C-terminal domain in its interaction with the AcrB multidrug efflux pump. J Bacteriol. 2003;185:5349-56 pubmed least two other resistance-nodulation-division family pumps, AcrD and AcrF, in addition to its cognate partner, AcrB. We found that, among other E...
  34. Potrykus J, Wegrzyn G. The acrAB locus is involved in modulating intracellular acetyl coenzyme A levels in a strain of Escherichia coli CM2555 expressing the chloramphenicol acetyltransferase (cat) gene. Arch Microbiol. 2003;180:362-6 pubmed
    ..However, our results show also that this is a genetic background-specific phenomenon, as the decrease in acetyl coenzyme A level is not evident in a cat-bearing DeltaacrAB derivative of the commonly used strain C600. ..
  35. Zgurskaya H. Covalently linked AcrB giant offers a new powerful tool for mechanistic analysis of multidrug efflux in bacteria. J Bacteriol. 2009;191:1727-8 pubmed publisher
  36. Kincses A, Szabó A, Saijo R, Watanabe G, Kawase M, Molnar J, et al. Fluorinated Beta-diketo Phosphorus Ylides Are Novel Efflux Pump Inhibitors in Bacteria. In Vivo. 2016;30:813-817 pubmed
    ..activity in multidrug efflux pump system consisting of the subunits acridine-resistance proteins A and B (AcrA and AcrB) and the multidrug efflux pump outer membrane factor TolC (TolC) of Escherichia coli K-12 AG100 strain and its ..
  37. Ge Q, Yamada Y, Zgurskaya H. The C-terminal domain of AcrA is essential for the assembly and function of the multidrug efflux pump AcrAB-TolC. J Bacteriol. 2009;191:4365-71 pubmed publisher
    ..In contrast, this domain remains proteolytically labile in cells producing only one of the AcrB or TolC components of the complex...
  38. Kamicker B, Sweeney M, Kaczmarek F, Dib Hajj F, Shang W, Crimin K, et al. Bacterial efflux pump inhibitors. Methods Mol Med. 2008;142:187-204 pubmed publisher
    ..In whole bacterial cells synergism antagonism or indifference of the combination of an antibiotic with the putative inhibitor is determined and this is then confirmed by quantitating viable bacterial cells in liquid culture over 24 h. ..
  39. Schmidt T, Raunest M, Fischer N, Reith D, Kandt C. Computer simulations suggest direct and stable tip to tip interaction between the outer membrane channel TolC and the isolated docking domain of the multidrug RND efflux transporter AcrB. Biochim Biophys Acta. 2016;1858:1419-26 pubmed publisher
    ..Although representing one of the best studied efflux systems, the question of how AcrB and TolC interact is still unclear as the available experimental data suggest that either both proteins interact in ..
  40. Tian H, Beckwith J. Genetic screen yields mutations in genes encoding all known components of the Escherichia coli signal recognition particle pathway. J Bacteriol. 2002;184:111-8 pubmed
    ..all of the mutations caused defects in the membrane insertions of three topologically distinct membrane proteins, AcrB, MalF, and FtsQ...
  41. Rand J, Danby S, Greenway D, England R. Increased expression of the multidrug efflux genes acrAB occurs during slow growth of Escherichia coli. FEMS Microbiol Lett. 2002;207:91-5 pubmed
    ..Slow growth rate regulation of acrAB transcription does not require the presence of the stationary-phase sigma factor. A putative gearbox consensus sequence was identified at the -10 region of the acrAB promoter. ..
  42. Nagakubo S, Nishino K, Hirata T, Yamaguchi A. The putative response regulator BaeR stimulates multidrug resistance of Escherichia coli via a novel multidrug exporter system, MdtABC. J Bacteriol. 2002;184:4161-7 pubmed
    ..A BLAST search suggested that such a heteromultimer-type RND exporter constitutes a unique family among gram-negative organisms. ..
  43. Su C, Nikaido H, Yu E. Ligand-transporter interaction in the AcrB multidrug efflux pump determined by fluorescence polarization assay. FEBS Lett. 2007;581:4972-6 pubmed
    The AcrB of Escherichia coli pumps out a wide range of compounds, including most of the currently available antibiotics, and contributes significantly to the serious problem of multidrug resistance of pathogenic bacteria...
  44. Pos K. Trinity revealed: Stoichiometric complex assembly of a bacterial multidrug efflux pump. Proc Natl Acad Sci U S A. 2009;106:6893-4 pubmed publisher
  45. Le T, Emonet T, Harlepp S, Guet C, Cluzel P. Dynamical determinants of drug-inducible gene expression in a single bacterium. Biophys J. 2006;90:3315-21 pubmed
    ..Single-cell experiments together with numerical simulations suggest that such pulsating response in drug-inducible genetic systems is a property emerging from the dependence of drug-inducible transcription on multidrug efflux systems. ..
  46. Hobbs E, Yin X, Paul B, Astarita J, Storz G. Conserved small protein associates with the multidrug efflux pump AcrB and differentially affects antibiotic resistance. Proc Natl Acad Sci U S A. 2012;109:16696-701 pubmed publisher
    ..Co-purification of AcrZ with AcrB, in the absence of both AcrA and TolC, two-hybrid assays and suppressor mutations indicate that this interaction ..
  47. Fernandez Recio J, Walas F, Federici L, Venkatesh Pratap J, Bavro V, Miguel R, et al. A model of a transmembrane drug-efflux pump from Gram-negative bacteria. FEBS Lett. 2004;578:5-9 pubmed
    ..trimeric outer-membrane protein TolC, which is an allosteric channel, the trimeric inner-membrane proton-antiporter AcrB, and the periplasmic protein, AcrA...
  48. Kinana A, Vargiu A, Nikaido H. Effect of site-directed mutations in multidrug efflux pump AcrB examined by quantitative efflux assays. Biochem Biophys Res Commun. 2016;480:552-557 pubmed publisher
    The Resistance-Nodulation-Division (RND) family transporter AcrB plays a major role in the intrinsic and increased resistance of Escherichia coli to a large number of antibiotics...
  49. Lobedanz S, Bokma E, Symmons M, Koronakis E, Hughes C, Koronakis V. A periplasmic coiled-coil interface underlying TolC recruitment and the assembly of bacterial drug efflux pumps. Proc Natl Acad Sci U S A. 2007;104:4612-7 pubmed
    ..A key feature of this positioning is that it allows space for the proposed movement of the inner coil of TolC during transition to its open state. ..
  50. Veesler D, Blangy S, Cambillau C, Sciara G. There is a baby in the bath water: AcrB contamination is a major problem in membrane-protein crystallization. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2008;64:880-5 pubmed publisher
    ..that the crystals consisted of an Escherichia coli contaminating protein, acriflavine resistance protein B (AcrB), that was present at less than 5% in the protein preparations...
  51. Ma D, Cook D, Alberti M, Pon N, Nikaido H, Hearst J. Genes acrA and acrB encode a stress-induced efflux system of Escherichia coli. Mol Microbiol. 1995;16:45-55 pubmed
    Defined mutations of acrA or acrB (formerly acrE) genes increased the susceptibility of Escherichia coli to a range of small inhibitor molecules...
  52. Yang S, Lopez C, Zechiedrich E. Quorum sensing and multidrug transporters in Escherichia coli. Proc Natl Acad Sci U S A. 2006;103:2386-91 pubmed
    ..These results support a model in which a natural function of AcrAB/TolC and NorE is to export signals for cell-cell communication. Drugs exported by pumps may resemble communication molecules normally exuded. ..
  53. Linde H, Notka F, Metz M, Kochanowski B, Heisig P, Lehn N. In vivo increase in resistance to ciprofloxacin in Escherichia coli associated with deletion of the C-terminal part of MarR. Antimicrob Agents Chemother. 2000;44:1865-8 pubmed
    ..In conclusion, the deletion of A1821 in marR in the clinical isolate EP2 caused an increase in the MICs of CIP and unrelated antibiotics. Presumably, the C-terminal part of MarR is necessary for proper repressor function. ..
  54. Stubbings W, Bostock J, Ingham E, Chopra I. Deletion of the multiple-drug efflux pump AcrAB in Escherichia coli prolongs the postantibiotic effect. Antimicrob Agents Chemother. 2005;49:1206-8 pubmed
    ..With specific assays for tetracycline and erythromycin, a direct link between intracellular persistence of antibiotics and maintenance of the PAE was established. ..
  55. Gotoh N, Murata T, Ozaki T, Kimura T, Kondo A, Nishino T. Intrinsic resistance of Escherichia coli to mureidomycin A and C due to expression of the multidrug efflux system AcrAB-TolC: comparison with the efflux systems of mureidomycin-susceptible Pseudomonas aeruginosa. J Infect Chemother. 2003;9:101-3 pubmed
    ..These studies showed that the differences regarding the susceptibility of E. coli and P. aeruginosa to mureidomycin A and C may be explained by the expression of efflux systems that mediate resistance to mureidomycin A and C. ..
  56. Bohnert J, Kern W. Selected arylpiperazines are capable of reversing multidrug resistance in Escherichia coli overexpressing RND efflux pumps. Antimicrob Agents Chemother. 2005;49:849-52 pubmed
  57. Murakami S, Yamaguchi A. Multidrug-exporting secondary transporters. Curr Opin Struct Biol. 2003;13:443-52 pubmed
    ..A recent crystal structure determination of a major resistance nodulation division type multidrug exporter, AcrB in Escherichia coli, greatly advances our understanding of the multidrug export mechanism...
  58. Alekshun M, Levy S. Alteration of the repressor activity of MarR, the negative regulator of the Escherichia coli marRAB locus, by multiple chemicals in vitro. J Bacteriol. 1999;181:4669-72 pubmed
    ..It is proposed that these compounds can interact directly with MarR to affect its repressor activity. ..
  59. Tsukagoshi N, Aono R. Entry into and release of solvents by Escherichia coli in an organic-aqueous two-liquid-phase system and substrate specificity of the AcrAB-TolC solvent-extruding pump. J Bacteriol. 2000;182:4803-10 pubmed
    ..The AcrAB-TolC complex likely extrudes solvents with a log P(OW) in the range of 3.4 to 6.0 through a first-order reaction. The most favorable substrates for the efflux system were considered to be octane, heptane, and n-hexane. ..
  60. Fischer N, Kandt C. Porter domain opening and closing motions in the multi-drug efflux transporter AcrB. Biochim Biophys Acta. 2013;1828:632-41 pubmed publisher
  61. Zwama M, Yamasaki S, Nakashima R, Sakurai K, Nishino K, Yamaguchi A. Multiple entry pathways within the efflux transporter AcrB contribute to multidrug recognition. Nat Commun. 2018;9:124 pubmed publisher
    b>AcrB is the major multidrug exporter in Escherichia coli. Although several substrate-entrances have been identified, the specificity of these various transport paths remains unclear...
  62. Ababou A. New insights into the structural and functional involvement of the gate loop in AcrB export activity. Biochim Biophys Acta Proteins Proteom. 2018;1866:242-253 pubmed publisher
    b>AcrB is a major multidrug exporter in Escherichia coli and other Gram-negative bacteria. Its gate loop, located between the proximal and the distal pockets, have been reported to play important role in the export of many antibiotics...
  63. Baranova N, Nikaido H. The baeSR two-component regulatory system activates transcription of the yegMNOB (mdtABCD) transporter gene cluster in Escherichia coli and increases its resistance to novobiocin and deoxycholate. J Bacteriol. 2002;184:4168-76 pubmed
    ..We accordingly propose to rename yegMNOB as mdtABCD (mdt for multidrug transporter). Finally, the expression of two other genes, yicO and ygcL, was shown to be regulated by BaeR, but it is not known if they play any roles in resistance. ..
  64. Husain F, Nikaido H. Substrate path in the AcrB multidrug efflux pump of Escherichia coli. Mol Microbiol. 2010;78:320-30 pubmed publisher
    ..The drug molecule is captured by AcrB probably from the periplasm or the periplasm/inner membrane interface, and is passed through AcrB and then TolC to ..
  65. Paixão L, Rodrigues L, Couto I, Martins M, Fernandes P, de Carvalho C, et al. Fluorometric determination of ethidium bromide efflux kinetics in Escherichia coli. J Biol Eng. 2009;3:18 pubmed publisher
  66. Elkins C, Beenken K. Modeling the tripartite drug efflux pump archetype: structural and functional studies of the macromolecular constituents reveal more than their names imply. J Chemother. 2005;17:581-92 pubmed
    ..However, correct assembly of the components is still a matter of debate as is the functional contribution of each to the translocation of drug substrates over long distances spanning the Gram-negative cell envelope. ..
  67. Krishnamoorthy G, Tikhonova E, Zgurskaya H. Fitting periplasmic membrane fusion proteins to inner membrane transporters: mutations that enable Escherichia coli AcrA to function with Pseudomonas aeruginosa MexB. J Bacteriol. 2008;190:691-8 pubmed
    ..periplasmic membrane fusion protein that establishes a functional connection between the inner membrane transporter AcrB of the RND superfamily and the outer membrane channel TolC...
  68. Fang J, Yu L, Wu M, Wei Y. Dissecting the function of a protruding loop in AcrB trimerization. J Biomol Struct Dyn. 2013;31:385-92 pubmed publisher
    The resistance-nodulation-cell division family multidrug transporter Acriflavine resistance protein B (AcrB) from Eschericha coli is an obligate homotrimer...
  69. Shaheen B, Boothe D, Oyarzabal O, Wang C, Johnson C. Evaluation of the contribution of gyrA mutation and efflux pumps to fluoroquinolone and multidrug resistance in pathogenic Escherichia coli isolates from dogs and cats. Am J Vet Res. 2011;72:25-32 pubmed publisher
  70. Yamamoto K, Tamai R, Yamazaki M, Inaba T, Sowa Y, Kawagishi I. Substrate-dependent dynamics of the multidrug efflux transporter AcrB of Escherichia coli. Sci Rep. 2016;6:21909 pubmed publisher
    ..The only constitutively expressed RND system of Escherichia coli consists of the inner membrane transporter AcrB, the membrane fusion protein AcrA, and the outer membrane channel TolC...
  71. Takatsuka Y, Nikaido H. Threonine-978 in the transmembrane segment of the multidrug efflux pump AcrB of Escherichia coli is crucial for drug transport as a probable component of the proton relay network. J Bacteriol. 2006;188:7284-9 pubmed
    Escherichia coli AcrB is a multidrug efflux transporter that recognizes multiple toxic chemicals and expels them from cells. It is a proton antiporter belonging to the resistance-nodulation-division (RND) superfamily...
  72. Song Y, Qin R, Pan X, Ouyang Q, Liu T, Zhai Z, et al. Design of New Antibacterial Enhancers Based on AcrB's Structure and the Evaluation of Their Antibacterial Enhancement Activity. Int J Mol Sci. 2016;17: pubmed
    ..found to have antibacterial enhancement activity against Escherichia coli via inhibition of the efflux pump AcrB. However, they were only effective against E. coli standard strains...
  73. Liu J, Pan Y, Yuan L, Wu H, Hu G, Chen Y. Genetic variations in the active efflux pump genes acrA/B and tolC in different drug-induced strains of Escherichia coli CVCC 1547. Genet Mol Res. 2013;12:2829-36 pubmed publisher tolC, G735A, that changed Ala-245 to Thr; strain AMK20 (and AMK30) had a Val-447 to Ile amino acid change in acrB. In addition to the missense mutations in these strains, we detected 7, 20, and 15 nonsense mutations in acrA, acrB,..
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    ..These results thus allow us to compare these efflux systems on a quantitative basis, if we can assume that the heterologous systems are fully functional in the E. coli host. ..
  75. Aoki S, Malinverni J, Jacoby K, Thomas B, Pamma R, Trinh B, et al. Contact-dependent growth inhibition requires the essential outer membrane protein BamA (YaeT) as the receptor and the inner membrane transport protein AcrB. Mol Microbiol. 2008;70:323-40 pubmed publisher
    ..of mutants resistant to CDI allowed us to identify BamA (YaeT) as the outer membrane receptor for CDI and AcrB as a potential downstream target. Notably, both BamA and AcrB are part of distinct multi-component machines...