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Title: Crystal structure of CmABCB1 multi-drug exporter in lipidic mesophase revealed by LCP-SFX
Authors: Pan, Dongqing  kyouindb  KAKEN_id  orcid (unconfirmed)
Oyama, Ryo
Sato, Tomomi
Nakane, Takanori
Mizunuma, Ryo
Matsuoka, Keita
Joti, Yasumasa
Tono, Kensuke
Nango, Eriko
Iwata, So
Nakatsu, Toru
Kato, Hiroaki
Author's alias: 潘, 東青
大山, 諒
佐藤, 友美
中根, 崇智
水沼, 諒
松岡, 敬太
城地, 保昌
登野, 健介
南後, 恵理子
岩田, 想
中津, 亨
加藤, 博章
Keywords: serial crystallography
protein structures
sample delivery
lipidic mesophase
multi-drug exporters
ABC transporters
Cyanidioschyzon merolae
Issue Date: Jan-2022
Publisher: International Union of Crystallography (IUCr)
Journal title: IUCrJ
Volume: 9
Issue: 1
Start page: 134
End page: 145
Abstract: CmABCB1 is a Cyanidioschyzon merolae homolog of human ABCB1, a well known ATP-binding cassette (ABC) transporter responsible for multi-drug resistance in various cancers. Three-dimensional structures of ABCB1 homologs have revealed the snapshots of inward- and outward-facing states of the transporters in action. However, sufficient information to establish the sequential movements of the open–close cycles of the alternating-access model is still lacking. Serial femtosecond crystallography (SFX) using X-ray free-electron lasers has proven its worth in determining novel structures and recording sequential conformational changes of proteins at room temperature, especially for medically important membrane proteins, but it has never been applied to ABC transporters. In this study, 7.7 mono­acyl­glycerol with cholesterol as the host lipid was used and obtained well diffracting microcrystals of the 130 kDa CmABCB1 dimer. Successful SFX experiments were performed by adjusting the viscosity of the crystal suspension of the sponge phase with hy­droxy­propyl methyl­cellulose and using the high-viscosity sample injector for data collection at the SACLA beamline. An outward-facing structure of CmABCB1 at a maximum resolution of 2.22 Å is reported, determined by SFX experiments with crystals formed in the lipidic cubic phase (LCP-SFX), which has never been applied to ABC transporters. In the type I crystal, CmABCB1 dimers interact with adjacent molecules via not only the nucleotide-binding domains but also the transmembrane domains (TMDs); such an interaction was not observed in the previous type II crystal. Although most parts of the structure are similar to those in the previous type II structure, the substrate-exit region of the TMD adopts a different configuration in the type I structure. This difference between the two types of structures reflects the flexibility of the substrate-exit region of CmABCB1, which might be essential for the smooth release of various substrates from the transporter.
Description: がんの多剤排出の原因となっているABCトランスポーターの立体構造をSACLAのX線自由電子レーザーを用いて決定. 京都大学プレスリリース. 2021-12-23.
Rights: This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
DOI(Published Version): 10.1107/S2052252521011611
PubMed ID: 35059217
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