Recombinant Escherichia coli Multidrug efflux pump subunit AcrB (acrB), partial

1. It has been demonstrated that an intact AcrAB-TolC efflux pump is crucial to the development of bacterial quinolone resistance. Its activity is complemented by expression of the alternative AcrEF efflux pump. PMID: 28520511
2. Data show that the conformational changes occurring in multidrug resistance-associated protein AcrB enable the formation of a layer of structured waters on the internal surface of the transport channel. PMID: 29339082
3. the gate loop mutations effects on AcrB solution energetics (fold, stability, molecular dynamics) and on the in vivo efflux of Erythromycin and Doxorubicin. Finally, we discuss the efflux and the discrepancy between the structural and the functional experiments for Erythromycin in these gate loop mutants. PMID: 29126836
4. The T37W/A100W double mutant AcrB exports ethidium bromide (EtBr) more actively than wild-type AcrB. PMID: 29317622
5. Energy-coupling mechanism of the multidrug resistance transporter AcrB: Evidence for membrane potential-driving hypothesis through mutagenic analysis. PMID: 28497315
6. Ten phosphorus ylides were compared 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) and in AcrAB-TolC-deletion. PMID: 27815466
7. Data show that CsrA binds directly to the 5' end of the transcript encoding AcrAB. PMID: 29040729
8. It has been found that both AcrA and AcrB lasted for approximately 6 days in live E. coli cells, and the stability of AcrB depended on the presence of AcrA but not on active antibiotic efflux. PMID: 27549795
9. Two phenylalanine residues located adjacent to the substitution sensitive glycine residues of acrB play a role in blocking the pathway upon rigidification of the loop, since the removal of the phenyl rings from the rigid loop restores drug transport activity PMID: 28987732
10. Our data show for the first time effects of various substrate-binding pocket mutations on the kinetics of efflux of two substrates by the AcrB pump. They also confirm interactions between substrates and drugs predicted by MD simulation studies, and also reveal areas that need future research. PMID: 27789287
11. Dihydroartemisinine 27 (DHA27) reduced multidrug resistance-associated protein acrB's mRNA expression in a dose-dependent manner. PMID: 27869748
12. AcrBA-TolC complex becomes unstable upon the induction of AcrD, which presumably replaces AcrB in the ternary complex. Such instability is suppressed upon the addition of AcrB-specific substrates. The assembly of resistance-nodulation-cell division-type efflux system is a regulated dynamic process that provides bacteria with a highly flexible repertoire of survival strategies to cope with a wide spectrum of antibiotics. PMID: 26916090
13. TolC-AcrB interaction only stable on the simulated time scale when both proteins engage in a tip to tip manner. PMID: 27045078
14. multiple deletion of acrB, acrD, and mdtABC resulted in a significant decrease in enterobactin export and that plasmids carrying the acrAB, acrD, or mdtABC genes restored the decrease in enterobactin export exhibited by the DeltaacrB acrD mdtABC mutant. PMID: 25259870
15. Switch-loop flexibility affects transport of large drugs by the promiscuous AcrB multidrug efflux transporter. PMID: 24914123
16. Results suggested that the unfolding of the trimeric AcrB started with a local structural rearrangement. PMID: 24715637
17. AcrAB-TolC pump effluxes regulate cellular metabolites that are toxic and have a signaling role. PMID: 24043404
18. Genetic defects in SoxS, MarA, or AcrB underlie superoxide-mediated protection of Escherichia coli from antimicrobials. PMID: 23979754
19. In addition to the missense mutations in these strains, we detected 7, 20, and 15 nonsense mutations in acrA, acrB, and tolC, respectively. PMID: 24065639
20. Data indicate that not all conserved residues are important for AcrB function and not all critical residues are conserved. PMID: 22877148
21. analysis of porter domain opening and closing motions in the multi-drug efflux transporter AcrB PMID: 23088914
22. used molecular dynamics simulation to examine the binding of nine substrates, two inhibitors, and two nonsubstrates to the distal binding pocket of AcrB, identified earlier by X-ray crystallography PMID: 23175790
23. Data show that AcrZ (formerly named YbhT) associates with the AcrAB-TolC complex. PMID: 23010927
24. insight from mutagenesis studies on AcrB trimer stability and efflux activity PMID: 22163011
25. Four amino acid residues in the vestibule of AcrB play roles role in substrate transport. PMID: 21856849
26. The structural characterization results suggest that the oligomerization of AcrB occurs through a three-stage pathway involving folded monomers. PMID: 21664361
27. fluoroquinolone resistance appeared to be a stepwise phenomenon, with MIC increasing as point mutations in gyrA increased, but high-level- and multidrug resistance associated with fluoroquinolone resistance reflected overexpression of AcrAB efflux pump PMID: 21194332
28. Substrate enters AcrB from the lower part of the cleft before binding to the binding pocket PMID: 20804453
29. Performed extensive targeted molecular dynamics simulations mimicking the functional rotation of AcrB containing doxorubicin. PMID: 20548943
30. ligands bind not only to the wall of central cavity but also to a new periplasmic site within the deep external depression formed by the C-terminal periplasmic loop PMID: 16166543
31. The observed pulsating behavior in inducible transcription of acrB is a systems property arising from the dependence of gene expression on multidrug resistance determinants. PMID: 16461398
32. crystal structures of AcrB with and without substrates PMID: 16915237
33. crystallographic structure of trimeric AcrB determined at 2.9 and 3.0 angstrom resolution; structural data imply an alternating access mechanism and a novel peristaltic mode of drug transport by this type of transporter PMID: 16946072
34. Thr978 functions through hydrogen bonding with Asp407 and protonation of the latter alters the salt bridging and hydrogen bonding pattern in the proton relay network, thus initiating a series of conformational changes that result in drug extrusion. PMID: 17015667
35. x-ray structures of four AcrB mutants, the D407A, D408A, K940A, and T978A mutants, in which the structure of this tight electrostatic network is expected to become disrupted; these mutant proteins revealed remarkably similar conformations PMID: 17015668
36. The crystal structure of trimeric AcrB in complex with a designed ankyrin-repeat protein inhibitor suggests a transport pathway not through the central pore but through the identified channels in the individual AcrB subunits. PMID: 17194213
37. analysis of the TolC/AcrAB complex from E. coli PMID: 17360572
38. AcrB forms a mixture of quaternary structures (from monomer to heavy oligomer) in detergent solution. PMID: 17467658
39. This study showed that conformational changes, including the closure of the external cleft in the periplasmic domain, are required for drug transport by AcrB. PMID: 17905989
40. Measurement of the affinity of ligands to AcrB protein. PMID: 17910961
41. The results suggest that AcrA, AcrB and TolC components of multidrug efflux pumps do not associate in an "all-or-nothing" fashion but accommodate a certain degree of flexibility. PMID: 18024521
42. The results support the presence of the asymmetric AcrB trimer in E. coli membranes and the functional rotation mechanism. PMID: 18223659
43. AcrS represses the gene expression of multidrug efflux genes, acrA and acrB. PMID: 18567659
44. Phenylalanine point mutations in the hydrophobic binding pocket in AcrB alters drug susceptibility. PMID: 18849422
45. structure of AcrB in complex with deoxycholate at 3.85 A resolution; evidence suggests that bile acid is transported out of the cell via the periplasmic vestibule of the AcrAB-TolC complex PMID: 19023693
46. intact cells of E coli containing the intact multiprotein complex AcrB-AcrA-TolC are used to measure the kinetic constants for various cephalosporins PMID: 19307562
47. Study conclude that the C-terminal domain of AcrA plays an important role in the assembly and function of AcrAB-TolC efflux pump. PMID: 19411330
48. Membrane-located carboxylates play a substantial role as a central element of the proton translocation pathway in AcrB and other members of the resistance nodulation and cell division superfamily. PMID: 19425588
49. AcrB trimer shows different conformations of each monomer showing a potential rotational peristaltic pump mechanism for transport PMID: 16946072

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KEGG: ecj:JW0451

STRING: 316385.ECDH10B_0418