Transport Across Two Membrane Bilayers in E. coli by Efflux Pumps of Different Dimensions: Transport by efflux pumps of diffeent dimentions

Ling Yang, Ankit Pandeya, Lan Li, Isoiza Ojo, Zhenyu Li, Yinan Wei

Research output: Contribution to journalArticlepeer-review


AcrAB-TolC and CusBAC are two of the most well-studied Resistance-Nodulation-Division (RND) family tripartite efflux pumps in E. coli. AcrAB-TolC is a multidrug efflux system, while CusBAC transports Cu(I), Cu(II) and Ag(I). The RND pump complexes span both the inner membrane (IM) and the outer membrane (OM). The long axis dimension of the fully assembled AcrAB-TolC is ∼3 nm longer than that of CusBAC. To probe if these two efflux systems with different dimensions affect each other when they need to work simultaneously in the same cell, two real-time assays were used to monitor the efflux activities of these two pumps and their impact on each other. The results showed that the presence of AcrAB-TolC substrates accelerated the accumulation of Cu(I) in BW25113 but not in BW25113ΔcusBA or BW25113ΔtolC strains. Similarly, the presence of Ag(I) slowed down the Nile red efflux in the parent strain more significantly than in the CusBA deficient mutant. To further investigate the impact of the OM/IM distance on the function of these tripartite complexes, we experimented with strains lacking the lipoprotein Lpp or containing Lpp mutant of different lengths. Data from efflux/accumulation assays and susceptibility tests revealed that mutation of Lpp resulted in functional deficiency of both AcrAB-TolC and CusBAC. In conclusion, this study demonstrated that when AcrAB-TolC and CusBAC functioned simultaneously, it took the cell a few minutes to adjust. Furthermore, the presence of Lpp of proper length is important to support full efflux activity of transporters spanning both membrane layers in E. coli.

Original languageEnglish
Article number167376
JournalJournal of Molecular Biology
Issue number2
StatePublished - Jan 30 2022

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Ltd


  • OM/IM distance
  • cell envelope
  • nile red efflux
  • periplasmic space
  • protein complex assembly

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Molecular Biology


Dive into the research topics of 'Transport Across Two Membrane Bilayers in E. coli by Efflux Pumps of Different Dimensions: Transport by efflux pumps of diffeent dimentions'. Together they form a unique fingerprint.

Cite this