Insight into the acrab-tolc complex assembly process learned from competition studies

Prasangi Rajapaksha, Isoiza Ojo, Ling Yang, Ankit Pandeya, Thilini Abeywansha, Yinan Wei

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The RND family efflux pump AcrAB-TolC in E. coli and its homologs in other Gram-negative bacteria are major players in conferring multidrug resistance to the cells. While the structure of the pump complex has been elucidated with ever-increasing resolution through crystallography and Cryo-EM efforts, the dynamic assembly process remains poorly understood. Here, we tested the effect of overexpressing functionally defective pump components in wild type E. coli cells to probe the pump assembly process. Incorporation of a defective component is expected to reduce the efflux efficiency of the complex, leading to the so called “dominant negative” effect. Being one of the most intensively studied bacterial multidrug efflux pumps, many AcrA and AcrB mutations have been reported that disrupt efflux through different mechanisms. We examined five groups of AcrB and AcrA mutants, defective in different aspects of assembly and substrate efflux. We found that none of them demonstrated the expected dominant negative effect, even when expressed at concentrations many folds higher than their genomic counterpart. The assembly of the AcrAB-TolC complex appears to have a proof-read mechanism that effectively eliminated the formation of futile pump complex.

Original languageEnglish
Article number830
JournalAntibiotics
Volume10
Issue number7
DOIs
StatePublished - Jul 2021

Bibliographical note

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • Assembly
  • Dominant negative effect
  • Mutation
  • Protein-protein interaction
  • RND pump

ASJC Scopus subject areas

  • General Pharmacology, Toxicology and Pharmaceutics
  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)
  • Biochemistry
  • Microbiology

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