6sgr
From Proteopedia
Cryo-EM structure of Escherichia coli AcrBZ and DARPin in Saposin A-nanodisc with cardiolipin
Structural highlights
Function[ACRB_ECOLI] AcrAB is a drug efflux protein with a broad substrate specificity.[1] [2] [3] [ACRZ_ECOLI] AcrA-AcrB-AcrZ-TolC is a drug efflux protein complex with a broad substrate specificity. This protein binds to AcrB and is required for efflux of some but not all substrates, suggesting it may influence the specificity of drug export.[4] Publication Abstract from PubMedThe small protein AcrZ in Escherichia coli interacts with the transmembrane portion of the multidrug efflux pump AcrB and increases resistance of the bacterium to a subset of the antibiotic substrates of that transporter. It is not clear how the physical association of the two proteins selectively changes activity of the pump for defined substrates. Here, we report cryo-EM structures of AcrB and the AcrBZ complex in lipid environments, and comparisons suggest that conformational changes occur in the drug-binding pocket as a result of AcrZ binding. Simulations indicate that cardiolipin preferentially interacts with the AcrBZ complex, due to increased contact surface, and we observe that chloramphenicol sensitivity of bacteria lacking AcrZ is exacerbated when combined with cardiolipin deficiency. Taken together, the data suggest that AcrZ and lipid cooperate to allosterically modulate AcrB activity. This mode of regulation by a small protein and lipid may occur for other membrane proteins. Interactions of a Bacterial RND Transporter with a Transmembrane Small Protein in a Lipid Environment.,Du D, Neuberger A, Orr MW, Newman CE, Hsu PC, Samsudin F, Szewczak-Harris A, Ramos LM, Debela M, Khalid S, Storz G, Luisi BF Structure. 2020 Apr 16. pii: S0969-2126(20)30095-2. doi:, 10.1016/j.str.2020.03.013. PMID:32348749[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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