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Updated: Apr 11, 2026

Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System
Published on: January 5, 2024
Molecular architecture of the bacterial tripartite multidrug efflux pump focusing on the adaptor bridging model
Saemee Song1, Jin-Sik Kim, Kangseok Lee
1Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea.
Abstract:
Gram-negative bacteria expel a wide range of toxic substances through tripartite drug efflux pumps consisting of an inner membrane transporter, an outer membrane channel protein, and a periplasmic adaptor protein. These pumps form tripartite assemblies which can span the entire cell envelope, including the inner and outer membranes. There have been controversial findings regarding the assembly of the individual components in tripartite drug efflux pumps. Recent structural and functional studies have advanced our understanding of the assembly and working mechanisms of the pumps. Here, we re-evaluate the assembly models based on recent structural and functional studies. In particular, this study focuses on the 'adaptor bridging model', highlighting the intermeshing cogwheel-like interactions between the tip regions of the outer membrane channel protein and the periplasmic adaptor protein in the hexameric assembly.
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