Structural and functional analysis of the promiscuous AcrB and AdeB efflux pumps suggests different drug binding mechanisms.
Alina Ornik-ChaJulia WilhelmJessica KobylkaHanno SjutsAttilio Vittorio VargiuGiuliano MallociJulian ReitzAnja SeybertAchilleas S FrangakisKlaas Martinus PosPublished in: Nature communications (2021)
Upon antibiotic stress Gram-negative pathogens deploy resistance-nodulation-cell division-type tripartite efflux pumps. These include a H+/drug antiporter module that recognizes structurally diverse substances, including antibiotics. Here, we show the 3.5 Å structure of subunit AdeB from the Acinetobacter baumannii AdeABC efflux pump solved by single-particle cryo-electron microscopy. The AdeB trimer adopts mainly a resting state with all protomers in a conformation devoid of transport channels or antibiotic binding sites. However, 10% of the protomers adopt a state where three transport channels lead to the closed substrate (deep) binding pocket. A comparison between drug binding of AdeB and Escherichia coli AcrB is made via activity analysis of 20 AdeB variants, selected on basis of side chain interactions with antibiotics observed in the AcrB periplasmic domain X-ray co-structures with fusidic acid (2.3 Å), doxycycline (2.1 Å) and levofloxacin (2.7 Å). AdeABC, compared to AcrAB-TolC, confers higher resistance to E. coli towards polyaromatic compounds and lower resistance towards antibiotic compounds.
Keyphrases
- gram negative
- multidrug resistant
- electron microscopy
- acinetobacter baumannii
- escherichia coli
- resting state
- functional connectivity
- drug resistant
- high resolution
- klebsiella pneumoniae
- pseudomonas aeruginosa
- binding protein
- single cell
- dna binding
- adverse drug
- drinking water
- magnetic resonance
- drug induced
- gene expression
- biofilm formation
- magnetic resonance imaging
- molecular dynamics simulations
- cystic fibrosis
- cell therapy
- mass spectrometry
- heat stress
- mesenchymal stem cells
- genome wide
- candida albicans
- contrast enhanced