Language
English
Publication Date
6-3-2025
Journal
Communications Biology
DOI
10.1038/s42003-025-08236-z
PMID
40461577
PMCID
PMC12134334
PubMedCentral® Posted Date
6-3-2025
PubMedCentral® Full Text Version
Post-print
Abstract
The MacAB-TolC tripartite efflux pump is widely distributed in Gram-negative bacteria, extruding antibiotics and virulence factors that lead to multidrug resistance and pathogenicity. However, the in situ structure and assembly mechanism of MacAB-TolC remain unclear. Here, we resolve the in situ structures of the MacAB-TolC efflux pump in Escherichia coli by electron cryo-tomography and subtomogram averaging. In the cells without antibiotic treatment, we observe a fully assembled MacAB-TolC pump. When Escherichia coli cells are treated with erythromycin, in addition to the tripartite pumps, we also discover the emergence of MacA-TolC subcomplexes without MacB, indicating flexible binding of MacB in the presence of an antibiotic substrate, which is further validated by in vivo photo-crosslinking results. Together, our data suggest the in situ assembly process of MacAB-TolC starts from the formation of MacA-TolC subcomplex, and provides insights into the design of efflux pump inhibitors.
Keywords
Escherichia coli Proteins, Escherichia coli, ATP-Binding Cassette Transporters, Bacterial Outer Membrane Proteins, Cryoelectron Microscopy, Membrane Transport Proteins, Anti-Bacterial Agents, Erythromycin, Cryoelectron tomography, Biochemistry
Published Open-Access
yes
Recommended Citation
Huo, Tong; Zhang, Wenfang; Yu, Zhili; et al., "In Situ Structure and Assembly of the ABC-Type Tripartite Pump MacAB-TolC" (2025). Faculty and Staff Publications. 3868.
https://digitalcommons.library.tmc.edu/baylor_docs/3868