ArticleAntimicrobial agents and chemotherapy2015
A fluorescent microplate assay quantifies bacterial efflux and demonstrates two distinct compound binding sites in AcrB.
Article in Antimicrobial agents and chemotherapy, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers.
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Who cites it
20 citing papers in PubMed, 48 citations in OpenAlex.
- EPS inhibitor treatment of Salmonella impacts evolution without selecting for resistance to biofilm inhibition.NPJ biofilms and microbiomes · 2025Article
- Boosting the Antibacterial Activity of Azithromycin on Multidrug-ResistantInternational journal of molecular sciences · 2023Article
- Colicin E1 opens its hinge to plug TolC.eLife · 2022Article
- Common recognition topology of mex transporters ofFrontiers in pharmacology · 2022Article
- Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria.Chemical reviews · 2021Review
- A palette of fluorophores that are differentially accumulated by wild-type and mutant strains ofMicrobiology (Reading, England) · 2021Article
- Determination of Drug Efflux Pump Efficiency in Drug-Resistant Bacteria Using MALDI-TOF MS.Antibiotics (Basel, Switzerland) · 2020Article
- Binding and Transport of Carboxylated Drugs by the Multidrug Transporter AcrB.Journal of molecular biology · 2020Article
- Mutations in the TolC Periplasmic Domain Affect Substrate Specificity of the AcrAB-TolC Pump.Frontiers in molecular biosciences · 2020Article
- Involvement of multiple influx and efflux transporters in the accumulation of cationic fluorescent dyes by Escherichia coli.BMC microbiology · 2019Article
- Molecular Interactions of Cephalosporins with the Deep Binding Pocket of the RND Transporter AcrB.The journal of physical chemistry. B · 2019Article
- An RND transporter in the monoterpene metabolism of Castellaniella defragrans.Biodegradation · 2019Article
- Proof of an Outer Membrane Target of the Efflux Inhibitor Phe-Arg-β-Naphthylamide from Random Mutagenesis.Molecules (Basel, Switzerland) · 2019Article
- Efflux Activity Differentially Modulates the Levels of Isoniazid and Rifampicin Resistance among Multidrug Resistant and Monoresistant Mycobacterium tuberculosis Strains.Antibiotics (Basel, Switzerland) · 2018Article
- Molecular Determinants of the Promiscuity of MexB and MexY Multidrug Transporters ofFrontiers in microbiology · 2018Article
- Molecular Rationale behind the Differential Substrate Specificity of Bacterial RND Multi-Drug Transporters.Scientific reports · 2017Article
- Review
- Evidence of a Substrate-Discriminating Entrance Channel in the Lower Porter Domain of the Multidrug Resistance Efflux Pump AcrB.Antimicrobial agents and chemotherapy · 2016Article
- Mechanisms of Resistance to Aminoglycoside Antibiotics: Overview and Perspectives.MedChemComm · 2016Article
- Compositional difference in antioxidant and antibacterial activity of all parts of the Carica papaya using different solvents.Chemistry Central journal · 2016Article
Corrections and comments
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Authors and funding
4 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
A direct assay of efflux by Escherichia coli AcrAB-TolC and related multidrug pumps would have great value in discovery of new Gram-negative antibiotics. The current understanding of how efflux is affected by the chemical structure and physical properties of molecules is extremely limited, derived from antibacterial data for compounds that inhibit growth of wild-type E. coli. We adapted a previously described fluorescent efflux assay to a 96-well microplate format that measured the ability of test compounds to compete for efflux with Nile Red (an environment-sensitive fluor), independent of antibacterial activity. We show that Nile Red and the lipid-sensitive probe DiBAC4-(3) [bis-(1,3-dibutylbarbituric acid)-trimethine oxonol] can quantify efflux competition in E. coli. We extend the previous findings that the tetracyclines compete with Nile Red and show that DiBAC4-(3) competes with macrolides. The extent of the competition shows a modest correlation with the effect of the acrB deletion on MICs within the compound sets for both dyes. Crystallographic studies identified at least two substrate binding sites in AcrB, the proximal and distal pockets. High-molecular-mass substrates bound the proximal pocket, while low-mass substrates occupied the distal pocket. As DiBAC4-(3) competes with macrolides but not with Nile Red, we propose that DiBAC4-(3) binds the proximal pocket and Nile Red likely binds the distal site. In conclusion, competition with fluorescent probes can be used to study the efflux process for diverse chemical structures and may provide information as to the site of binding and, in some cases, enable rank-ordering a series of related compounds by efflux.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.