Molecular architecture of the bacterial tripartite multidrug efflux pump focusing on the adaptor bridging model

• Published in: The journal of microbiology Vol. 53; no. 6; pp. 355 - 364
• Main Authors: Song, Saemee, Kim, Jin-Sik, Lee, Kangseok, Ha, Nam-Chul
• Format: Journal Article
• Language: English
• Published: Seoul The Microbiological Society of Korea 01.06.2015; Springer Nature B.V; 한국미생물학회
• Subjects: Agricultural biotechnology; Antibiotics; Bacteria; Bacterial Outer Membrane Proteins - chemistry; Bacterial Outer Membrane Proteins - metabolism; Biological Transport, Active; Biomedical and Life Sciences; Gram-negative bacteria; Gram-Negative Bacteria - chemistry; Gram-Negative Bacteria - metabolism; Life Sciences; Membrane Transport Proteins - chemistry; Membrane Transport Proteins - metabolism; Membranes; Microbiology; Minireview; Models, Biological; Models, Molecular; Periplasmic Proteins - chemistry; Periplasmic Proteins - metabolism; Protein Conformation; Protein Multimerization; Proteins; 생물학; South Korea; multidrug efflux pump; multidrug resistance; Gram-negative bacteria; TolC; structure
• ISSN: 1225-8873; 1976-3794
• DOI: 10.1007/s12275-015-5248-4

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.