National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
米国
Welch Foundation
米国
Damon Runyon Cancer Research Foundation
米国
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2021 タイトル: Molecular basis of cholesterol efflux via ABCG subfamily transporters. 著者: Yingyuan Sun / Jin Wang / Tao Long / Xiaofeng Qi / Linda Donnelly / Nadia Elghobashi-Meinhardt / Leticia Esparza / Jonathan C Cohen / Xiao-Song Xie / Helen H Hobbs / Xiaochun Li / 要旨: The ABCG1 homodimer (G1) and ABCG5-ABCG8 heterodimer (G5G8), two members of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter G family, are required for maintenance of cellular ...The ABCG1 homodimer (G1) and ABCG5-ABCG8 heterodimer (G5G8), two members of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter G family, are required for maintenance of cellular cholesterol levels. G5G8 mediates secretion of neutral sterols into bile and the gut lumen, whereas G1 transports cholesterol from macrophages to high-density lipoproteins (HDLs). The mechanisms used by G5G8 and G1 to recognize and export sterols remain unclear. Here, we report cryoelectron microscopy (cryo-EM) structures of human G5G8 in sterol-bound and human G1 in cholesterol- and ATP-bound states. Both transporters have a sterol-binding site that is accessible from the cytosolic leaflet. A second site is present midway through the transmembrane domains of G5G8. The Walker A motif of G8 adopts a unique conformation that accounts for the marked asymmetry in ATPase activities between the two nucleotide-binding sites of G5G8. These structures, along with functional validation studies, provide a mechanistic framework for understanding cholesterol efflux via ABC transporters.
平均露光時間: 1.8 sec. / 電子線照射量: 60 e/Å2 / フィルム・検出器のモデル: GATAN K3 (6k x 4k) / 撮影したグリッド数: 1 / 実像数: 4900
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解析
ソフトウェア
名称: REFMAC / バージョン: 5.8.0258 / 分類: 精密化
CTF補正
タイプ: PHASE FLIPPING AND AMPLITUDE CORRECTION
粒子像の選択
選択した粒子像数: 1443662
3次元再構成
解像度: 3.7 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 72323 / 対称性のタイプ: POINT
精密化
解像度: 3.68→213.25 Å / Cor.coef. Fo:Fc: 0.861 / SU B: 18.699 / SU ML: 0.266 / ESU R: 0.221 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD / 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
Rfactor
反射数
%反射
Rwork
0.39376
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-
obs
0.39376
407373
100 %
溶媒の処理
イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.2 Å / 溶媒モデル: MASK