Structural characterization of the EmrAB-TolC efflux complex from E. coli.
Gram-negative bacteria export a large variety of antimicrobial compounds by forming two-membrane spanning tripartite multidrug efflux systems composed of an inner membrane transporter, an outer membrane channel and a periplasmic adaptor protein. Here we present the co-expression, purification and first electron microscopy insights of the Escherichia coli EmrAB-TolC tripartite Major Facilitator Superfamily (MSF) efflux system as a whole complex stabilized by Amphipol polymer. The structure reveals a 33 nm long complex delineated by the Amphipol belt at both extremities. Comparison of projection structures of EmrAB-TolC and AcrAB-TolC indicates that the outer membrane protein TolC linked to the periplasmic adaptor EmrA protein form an extended periplasmic canal. The overall length of EmrAB-TolC complex is similar to that of AcrAB-TolC with a probable tip-to-tip interaction between EmrA and TolC unveiling how the adaptor protein connects TolC and EmrB embedded in the inner membrane.
['Yousefian|Narek|N|', 'Ornik-Cha|Alina|A|', 'Poussard|Sylvie|S|', 'Decossas|Marion|M|', 'Berbon|Melanie|M|', 'Daury|Laetitia|L|', 'Taveau|Jean-Christophe|JC|', 'Dupuy|Jean-William|JW|', 'Đorđević-Marquardt|Selena|S|', 'Lambert|Olivier|O|', 'Pos|Klaas M|KM|']
D001425:Bacterial Outer Membrane Proteins D004926:Escherichia coli D029968:Escherichia coli Proteins D008565:Membrane Proteins D026901:Membrane Transport Proteins D046912:Multiprotein Complexes D020836:Protein Structure, Quaternary
EmrAB-TolC Membrane transport Electron microscopy Major facilitator superfamily Drug efflux Tripartite multidrug efflux pump