Structure of the MacAB-TolC ABC-type tripartite multidrug efflux pump.Fitzpatrick, A.W.P., Llabres, S., Neuberger, A., Blaza, J.N., Bai, X.C., Okada, U., Murakami, S., van Veen, H.W., Zachariae, U., Scheres, S.H.W., Luisi, B.F., Du, D.
(2017) Nat Microbiol 2: 17070-17070
- PubMed: 28504659
- DOI: 10.1038/nmicrobiol.2017.70
- Primary Citation of Related Structures:
- PubMed Abstract:
The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by th ...
The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism.
Department of Life Science, Tokyo Institute of Technology, 4259-J2-17, Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan.,Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K.,Physics, School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 4NH, U.K.,MRC Mitochondrial Biology Unit, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY.,Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, U.K.,Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K.,Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, U.K.