[TOLC_ECOLI] Outer membrane channel, which is required for the function of several efflux systems such as AcrAB-TolC, AcrEF-TolC, EmrAB-TolC and MacAB-TolC. These systems are involved in export of antibiotics and other toxic compounds from the cell. TolC is also involved in import of colicin E1 into the cells.[1][2][3][4][5] [ACRB_ECOLI] AcrAB is a drug efflux protein with a broad substrate specificity.[6][7][8] [ACRA_ECO57] AcrA-AcrB-AcrZ-TolC is a drug efflux protein complex with broad substrate specificity that uses the proton motive force to export substrates. This subunit may act as an adapter protein that links AcrB and TolC stably together (By similarity).
Publication Abstract from PubMed
Bacterial efflux pumps confer multidrug resistance by transporting diverse antibiotics from the cell. In Gram-negative bacteria, some of these pumps form multi-protein assemblies that span the cell envelope. Here we report the near-atomic resolution cryoEM structures of the Escherichia coli AcrAB-TolC multidrug efflux pump in resting and drug transport states, revealing a quaternary structural switch that allosterically couples and synchronizes initial ligand binding with channel opening. Within the transport-activated state, the channel remains open even though the pump cycles through three distinct conformations. Collectively, our data provide a dynamic mechanism for the assembly and operation of the AcrAB-TolC pump.
An allosteric transport mechanism for the AcrAB-TolC Multidrug Efflux Pump.,Wang Z, Fan G, Hryc CF, Blaza JN, Serysheva II, Schmid MF, Chiu W, Luisi BF, Du D Elife. 2017 Mar 29;6. pii: e24905. doi: 10.7554/eLife.24905. PMID:28355133[9]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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↑ Murakami S, Nakashima R, Yamashita E, Matsumoto T, Yamaguchi A. Crystal structures of a multidrug transporter reveal a functionally rotating mechanism. Nature. 2006 Sep 14;443(7108):173-9. Epub 2006 Aug 16. PMID:16915237 doi:10.1038/nature05076
↑ Seeger MA, Schiefner A, Eicher T, Verrey F, Diederichs K, Pos KM. Structural asymmetry of AcrB trimer suggests a peristaltic pump mechanism. Science. 2006 Sep 1;313(5791):1295-8. PMID:16946072 doi:313/5791/1295
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↑ Wang Z, Fan G, Hryc CF, Blaza JN, Serysheva II, Schmid MF, Chiu W, Luisi BF, Du D. An allosteric transport mechanism for the AcrAB-TolC Multidrug Efflux Pump. Elife. 2017 Mar 29;6. pii: e24905. doi: 10.7554/eLife.24905. PMID:28355133 doi:http://dx.doi.org/10.7554/eLife.24905