EMD-12170

Single-particle
4.2 Å
EMD-12170 Deposition: 05/01/2021
Map released: 12/01/2022
Last modified: 10/07/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-12170

Multidrug resistance transporter BmrA mutant E504A bound with ATP, Mg, and Rhodamine 6G solved by Cryo-EM

EMD-12170

Single-particle
4.2 Å
EMD-12170 Deposition: 05/01/2021
Map released: 12/01/2022
Last modified: 10/07/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Bacillus subtilis
Sample: Multidrug resistance transporter from Bacillus subtilis bound with ATP, Mg, and Rhodamine 6G.
Fitted models: 7bg4 (Avg. Q-score: 0.309)

Deposition Authors: Wiseman B , Chaptal V
Substrate-bound and substrate-free outward-facing structures of a multidrug ABC exporter.
PUBMED: 35080979
DOI: doi:10.1126/sciadv.abg9215
ISSN: 2375-2548
Abstract:
Multidrug ABC transporters translocate drugs across membranes by a mechanism for which the molecular features of drug release are so far unknown. Here, we resolved three ATP-Mg2+-bound outward-facing conformations of the Bacillus subtilis (homodimeric) BmrA by x-ray crystallography and single-particle cryo-electron microscopy (EM) in detergent solution, one of them with rhodamine 6G (R6G), a substrate exported by BmrA when overexpressed in B. subtilis. Two R6G molecules bind to the drug-binding cavity at the level of the outer leaflet, between transmembrane (TM) helices 1-2 of one monomer and TM5'-6' of the other. They induce a rearrangement of TM1-2, highlighting a local flexibility that we confirmed by hydrogen/deuterium exchange and molecular dynamics simulations. In the absence of R6G, simulations show a fast postrelease occlusion of the cavity driven by hydrophobicity, while when present, R6G can move within the cavity, maintaining it open.