EMD-12170
Multidrug resistance transporter BmrA mutant E504A bound with ATP, Mg, and Rhodamine 6G solved by Cryo-EM
EMD-12170
Single-particle4.2 Å
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Map released: 12/01/2022
Last modified: 10/07/2024
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
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
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Substrate-bound and substrate-free outward-facing structures of a multidrug ABC exporter.
Chaptal V
,
Zampieri V
,
Wiseman B
,
Orelle C
,
Martin J
,
Nguyen KA
,
Gobet A
,
Di Cesare M
,
Magnard S
,
Javed W
,
Eid J,
Kilburg A
,
Peuchmaur M
,
Marcoux J
,
Monticelli L
,
Hogbom M
,
Schoehn G
,
Jault JM
,
Boumendjel A,
Falson P
(2022) Sci Adv , 8 , eabg9215 - eabg9215
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(2022) Sci Adv , 8 , eabg9215 - eabg9215
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.
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.