ジャーナル: Sci Adv / 年: 2022 タイトル: Substrate-bound and substrate-free outward-facing structures of a multidrug ABC exporter. 著者: Vincent Chaptal / Veronica Zampieri / Benjamin Wiseman / Cédric Orelle / Juliette Martin / Kim-Anh Nguyen / Alexia Gobet / Margot Di Cesare / Sandrine Magnard / Waqas Javed / Jad Eid / ...著者: Vincent Chaptal / Veronica Zampieri / Benjamin Wiseman / Cédric Orelle / Juliette Martin / Kim-Anh Nguyen / Alexia Gobet / Margot Di Cesare / Sandrine Magnard / Waqas Javed / Jad Eid / Arnaud Kilburg / Marine Peuchmaur / Julien Marcoux / Luca Monticelli / Martin Hogbom / Guy Schoehn / Jean-Michel Jault / Ahcène Boumendjel / Pierre Falson / 要旨: 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-Mg-bound outward-facing ...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-Mg-bound outward-facing conformations of the (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 . 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.
解像度: 3.95→28.42 Å / Cor.coef. Fo:Fc: 0.708 / Cor.coef. Fo:Fc free: 0.644 / 交差検証法: THROUGHOUT / SU Rfree Blow DPI: 1.354 詳細: 9 big cycles of 500 small cycles each. Refinement R values go up in the first cycles before going down and converging to a stable value in the later stages. Use of TLS refinement. Use of NCS, ...詳細: 9 big cycles of 500 small cycles each. Refinement R values go up in the first cycles before going down and converging to a stable value in the later stages. Use of TLS refinement. Use of NCS, strong initially, only loosened in the last stages of refinement Data displaying very strong anisotropy.