Interchangeability of periplasmic adaptor proteins AcrA and AcrE in forming functional efflux pumps with AcrD in Salmonella enterica serovar Typhimurium
| Autor: | Jessica M A Blair, Ilyas Alav, Vassiliy N. Bavro |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Salmonella typhimurium
Microbiology (medical) Mutant Serogroup medicine.disease_cause Microbiology 03 medical and health sciences Plasmid Bacterial Proteins medicine AcademicSubjects/MED00740 Pharmacology (medical) Escherichia coli Original Research 030304 developmental biology Pharmacology 0303 health sciences biology 030306 microbiology Membrane transport protein Chemistry Periplasmic space biology.organism_classification Anti-Bacterial Agents AcademicSubjects/MED00290 Infectious Diseases Salmonella enterica biology.protein Efflux Periplasmic Proteins AcademicSubjects/MED00230 Bacterial outer membrane |
| Zdroj: | Journal of Antimicrobial Chemotherapy |
| ISSN: | 1460-2091 0305-7453 |
| DOI: | 10.1093/jac/dkab237 |
| Popis: | Background Resistance-nodulation-division (RND) efflux pumps are important mediators of antibiotic resistance. RND pumps, including the principal multidrug efflux pump AcrAB-TolC in Salmonella, are tripartite systems with an inner membrane RND transporter, a periplasmic adaptor protein (PAP) and an outer membrane factor (OMF). We previously identified the residues required for binding between the PAP AcrA and the RND transporter AcrB and have demonstrated that PAPs can function with non-cognate transporters. AcrE and AcrD/AcrF are homologues of AcrA and AcrB, respectively. Here, we show that AcrE can interact with AcrD, which does not possess its own PAP, and establish that the residues previously identified in AcrB binding are also involved in AcrD binding. Methods The acrD and acrE genes were expressed in a strain lacking acrABDEF (Δ3RND). PAP residues involved in promiscuous interactions were predicted based on previously defined PAP-RND interactions and corresponding mutations generated in acrA and acrE. Antimicrobial susceptibility of the mutant strains was determined. Results Co-expression of acrD and acrE significantly decreased susceptibility of the Δ3RND strain to AcrD substrates, showing that AcrE can form a functional complex with AcrD. The substrate profile of Salmonella AcrD differed from that of Escherichia coli AcrD. Mutations targeting the previously defined PAP-RND interaction sites in AcrA/AcrE impaired efflux of AcrD-dependent substrates. Conclusions These data indicate that AcrE forms an efflux-competent pump with AcrD and thus presents an alternative PAP for this pump. Mutagenesis of the conserved RND binding sites validates the interchangeability of AcrA and AcrE, highlighting them as potential drug targets for efflux inhibition. |
| Databáze: | OpenAIRE |
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