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Conformational restriction shapes the inhibition of a multidrug efflux adaptor protein

ABSTRACT: Membrane efflux pumps play a major role in bacterial multidrug resistance. The tripartite multidrug efflux pump system from Escherichia coli, AcrAB-TolC, is a target for inhibition to lessen resistance development and restore antibiotic efficacy, with homologs in other ESKAPE pathogens. Here, we rationalize a mechanism of inhibition against the periplasmic adaptor protein, AcrA, using a combination of hydrogen/deuterium exchange mass spectrometry, cellular efflux assays, and molecular dynamics simulations. We define the structural dynamics of AcrA and find that an inhibitor can inflict long-range stabilisation across all four of its domains, whereas an interacting efflux substrate has minimal effect. Our results support a model where an inhibitor forms a molecular wedge within a cleft between the lipoyl and αβ domains of AcrA, diminishing its conformational transmission of drug-evoked signals from AcrB to TolC. This work provides molecular insights into multidrug adaptor protein function which could be valuable for developing antimicrobial therapeutics.

INSTRUMENT(S): Xevo G2-XS QTof, SYNAPT G2-Si, Q Exactive HF

ORGANISM(S): Escherichia Coli

SUBMITTER: Benjamin Russell Lewis

LAB HEAD: Eamonn Reading

PROVIDER: PXD041359 | Pride | 2023-06-01

REPOSITORIES: Pride

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