The assembly and disassembly of the AcrAB-TolC three-component multidrug efflux pump

Müller, Reinke T.; Pos, Klaas M.

doi:10.1515/hsz-2015-0150

Cited by 25 publications

(23 citation statements)

References 9 publications

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“…tolC is well known to be involved in the efflux of a great many substances because it is linked to a variety of inner-membrane efflux transporters [69,72,[120][121][122]. In this case the uptake of the majority of the palette was, as expected, greater than in the wild type in the tolC deletion strain.…”

Section: The Profiles Observed With Gene Knockouts Discriminate Influsupporting

confidence: 55%

A palette of fluorophores that are differentially accumulated by wild-type and mutant strains ofEscherichia coli: surrogate ligands for bacterial membrane transporters

Salcedo-Sora

Jindal

O’Hagan

et al. 2020

Preprint

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Our previous work had demonstrated that two commonly used fluorescent dyes that were accumulated by wild-type E. coli MG1655 were accumulated differentially in single-gene knockout strains, and also that they might be used as surrogates in flow cytometric transporter assays. We summarise the desirable properties of such stains, and here survey 143 candidate dyes. We triage them eventually (on the basis of signal, accumulation levels, and cost) to a palette of 39 commercially available and affordable fluorophores that are accumulated significantly by wild-type cells of the ‘Keio’ strain BW25113, as measured flow cytometrically. Cheminformatic analyses indicate both their similarities and their (much more considerable) structural differences. We describe the effects of pH and of the efflux pump inhibitor chlorpromazine on the accumulation. Even the ‘wild-type’ MG1655 and BW25113 strains can differ significantly in their ability to take up such dyes. We illustrate the highly differential uptake of our dyes into strains with particular lesions in, or overexpressed levels of, three particular transporters or transporter components (yhjV, yihN, and tolC). The relatively small collection of dyes described offers a rapid, inexpensive, convenient and valuable approach to the assessment of microbial physiology and transporter function.

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Section: The Profiles Observed With Gene Knockouts Discriminate Influsupporting

confidence: 55%

A palette of fluorophores that are differentially accumulated by wild-type and mutant strains ofEscherichia coli: surrogate ligands for bacterial membrane transporters

Salcedo-Sora

Jindal

O’Hagan

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…165 Considering these findings and the observation from Kralj et al that in E. coli a rapidly spiking (∼1 Hz) PMF coincided with the efflux of the potential AcrB substrate tetramethyl rhodamine methylester, 166 we and others have suggested that the AcrAB-TolC MDEP operates in a discontinuous fashion. 167 Some uncertainty still remains concerning the tripartite setup, since clear cross-linking between AcrB and TolC has been observed. 168 Moreover, the expression of genetic fusions between acrA and acrB in an E. coli acrAB strain resulted in drug resistance.…”

Section: Structural and Functional Dynamics Of The Acrab(z)-tolc Complexmentioning

confidence: 99%

AcrB: a mean, keen, drug efflux machine

Kobylka

Kuth

Müller

et al. 2019

Annals of the New York Academy of Sciences

118

135

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Gram-negative bacteria are intrinsically resistant against cytotoxic substances by means of their outer membrane and a network of multidrug efflux systems, acting in synergy. Efflux pumps from various superfamilies with broad substrate preferences sequester and pump drugs across the inner membrane to supply the highly polyspecific and powerful tripartite resistance-nodulation-cell division (RND) efflux pumps with compounds to be extruded across the outer membrane barrier. In Escherichia coli, the tripartite efflux system AcrAB-TolC is the archetype RND multiple drug efflux pump complex. The homotrimeric inner membrane component acriflavine resistance B (AcrB) is the drug specificity and energy transduction center for the drug/proton antiport process. Drugs are bound and expelled via a cycle of mainly three consecutive states in every protomer, constituting a flexible alternating access channel system. This review recapitulates the molecular basis of drug and inhibitor binding, including mechanistic insights into drug efflux by AcrB. It also summarizes 17 years of mutational analysis of the gene acrB, reporting the effect of every substitution on the ability of E. coli to confer resistance toward antibiotics (http://goethe.link/ AcrBsubstitutions). We emphasize the functional robustness of AcrB toward single-site substitutions and highlight regions that are more sensitive to perturbation.

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“…Due to the limited resolution, these studies were unable to identify the detailed interaction interfaces between the components. Moreover, the mechanism of pump assembly and channel opening is presently unclear (Müller and Pos, 2015; Zgurskaya et al, 2015) and requires detailed structural information of the pump in the different conformational states that accompany drug translocation. In this study, we report the near-atomic resolution cryoEM structures of the AcrAB-TolC pump captured in both resting and drug transport states.…”

Section: Introductionmentioning

confidence: 99%

An allosteric transport mechanism for the AcrAB-TolC multidrug efflux pump

Wang

Fan

Hryc

et al. 2017

eLife

208

358

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Bacterial efflux pumps confer multidrug resistance by transporting diverse antibiotics from the cell. In Gram-negative bacteria, some of these pumps form multi-protein assemblies that span the cell envelope. Here, we report the near-atomic resolution cryoEM structures of the Escherichia coli AcrAB-TolC multidrug efflux pump in resting and drug transport states, revealing a quaternary structural switch that allosterically couples and synchronizes initial ligand binding with channel opening. Within the transport-activated state, the channel remains open even though the pump cycles through three distinct conformations. Collectively, our data provide a dynamic mechanism for the assembly and operation of the AcrAB-TolC pump.DOI: http://dx.doi.org/10.7554/eLife.24905.001

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The assembly and disassembly of the AcrAB-TolC three-component multidrug efflux pump

Cited by 25 publications

References 9 publications

A palette of fluorophores that are differentially accumulated by wild-type and mutant strains ofEscherichia coli: surrogate ligands for bacterial membrane transporters

A palette of fluorophores that are differentially accumulated by wild-type and mutant strains ofEscherichia coli: surrogate ligands for bacterial membrane transporters

AcrB: a mean, keen, drug efflux machine

An allosteric transport mechanism for the AcrAB-TolC multidrug efflux pump

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