*Two first authors equally contributed to this work
Tripartite multidrug efflux systems of Gram-negative bacteria export a large variety of antimicrobial compounds at the expense of ATP or the proton motive force, thereby conferring resistance to a wide variety of antibiotics. Pseudomonas aeruginosa MexAB-OprM and Escherichia coli AcrAB-TolC, are prototypic proton motive force-driven efflux systems from Resistance Nodulation and cell Division (RND) family. These efflux systems, composed of an inner membrane transporter, an outer membrane channel and a periplasmic adaptor protein, are assumed to form ducts inside the periplasm, facilitating drug exit across the outer membrane. Using lipid nanodisc system, we recently reported the reconstitution of native MexAB-OprM tripartite system. Single particle analysis by electron microscopy revealed the lipid nanodisc-embedded inner and outer membrane protein components linked together via the MexA periplasmic adaptor protein .
Recently the replacement of detergent by specially designed amphiphilic molecules such as amphipol or styrene–maleic acid copolymers is an alternative option to stabilize the membrane proteins in a free-lipid environment. To further investigate key parameters controlling the formation of the tripartite system, we focus our study on MexA that in its mature form is anchored to the inner membrane via its palmitoyl moiety. To assess whether the lipid anchor is required for the reconstitution, we report here on the reconstitution of OprM and MexB in amphipol and compare with our previous results obtained with nanodiscs.
 Daury L, Orange F, Taveau JC, Verchère A, Monlezun L, Gounou C, Marreddy RK, Picard M, Broutin I, Pos KM, Lambert O (2016). Tripartite assembly of RND multidrug efflux pumps. Nat Commun. 7:10731.
To cite this abstract:Dimitri Salvador, Marie Glavier, Cyril Garnier, Martin Picard, Isabelle Broutin, Jean-Christophe Taveau, Laetitia Daury, Olivier Lambert; Tripartite assembly of RND multidrug efflux pumps in nanodisc and amphipol. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/tripartite-assembly-of-rnd-multidrug-efflux-pumps-in-nanodisc-and-amphipol/. Accessed: December 1, 2022
EMC Abstracts - https://emc-proceedings.com/abstract/tripartite-assembly-of-rnd-multidrug-efflux-pumps-in-nanodisc-and-amphipol/