Download MendeleyDistinct allosteric mechanisms of first-generation MsbA inhibitors.
Thelot, F.A., Zhang, W., Song, K., Xu, C., Huang, J., Liao, M.(2021) Science 374: 580-585
- PubMed: 34554829
- DOI: https://doi.org/10.1126/science.abi9009
- Primary Citation of Related Structures:
7MET, 7MEW, 7RIT - PubMed Abstract:
ATP-binding cassette (ABC) transporters couple adenosine 5′-triphosphate (ATP) hydrolysis to substrate transport across biological membranes. Although many are promising drug targets, their mechanisms of modulation by small-molecule inhibitors remain largely unknown. Two first-generation inhibitors of the MsbA transporter, tetrahydrobenzothiophene 1 (TBT1) and G247, induce opposite effects on ATP hydrolysis. Using single-particle cryo–electron microscopy and functional assays, we show that TBT1 and G247 bind adjacent yet separate pockets in the MsbA transmembrane domains. Two TBT1 molecules asymmetrically occupy the substrate-binding site, which leads to a collapsed inward-facing conformation with decreased distance between the nucleotide-binding domains (NBDs). By contrast, two G247 molecules symmetrically increase NBD distance in a wide inward-open state of MsbA. The divergent mechanisms of action of these MsbA inhibitors provide important insights into ABC transporter pharmacology.
Organizational Affiliation:
Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
