ジャーナル: Science / 年: 2017 タイトル: Fibril structure of amyloid-β(1-42) by cryo-electron microscopy. 著者: Lothar Gremer / Daniel Schölzel / Carla Schenk / Elke Reinartz / Jörg Labahn / Raimond B G Ravelli / Markus Tusche / Carmen Lopez-Iglesias / Wolfgang Hoyer / Henrike Heise / Dieter Willbold ...著者: Lothar Gremer / Daniel Schölzel / Carla Schenk / Elke Reinartz / Jörg Labahn / Raimond B G Ravelli / Markus Tusche / Carmen Lopez-Iglesias / Wolfgang Hoyer / Henrike Heise / Dieter Willbold / Gunnar F Schröder / 要旨: Amyloids are implicated in neurodegenerative diseases. Fibrillar aggregates of the amyloid-β protein (Aβ) are the main component of the senile plaques found in brains of Alzheimer's disease ...Amyloids are implicated in neurodegenerative diseases. Fibrillar aggregates of the amyloid-β protein (Aβ) are the main component of the senile plaques found in brains of Alzheimer's disease patients. We present the structure of an Aβ(1-42) fibril composed of two intertwined protofilaments determined by cryo-electron microscopy (cryo-EM) to 4.0-angstrom resolution, complemented by solid-state nuclear magnetic resonance experiments. The backbone of all 42 residues and nearly all side chains are well resolved in the EM density map, including the entire N terminus, which is part of the cross-β structure resulting in an overall "LS"-shaped topology of individual subunits. The dimer interface protects the hydrophobic C termini from the solvent. The characteristic staggering of the nonplanar subunits results in markedly different fibril ends, termed "groove" and "ridge," leading to different binding pathways on both fibril ends, which has implications for fibril growth.
凍結剤: ETHANE / 装置: FEI VITROBOT MARK IV 詳細: 2.5 microL sample was applied to the grid, blotted for 2.5 s before plunging..
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電子顕微鏡法
顕微鏡
FEI TECNAI ARCTICA
撮影
フィルム・検出器のモデル: FEI FALCON III (4k x 4k) 検出モード: INTEGRATING / 撮影したグリッド数: 1 / 実像数: 2026 / 平均露光時間: 2.0 sec. / 平均電子線量: 24.0 e/Å2
電子線
加速電圧: 200 kV / 電子線源: FIELD EMISSION GUN
電子光学系
照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELD / Cs: 2.7 mm / 倍率(公称値): 110000
実験機器
モデル: Talos Arctica / 画像提供: FEI Company
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画像解析
最終 再構成
使用したクラス数: 1 想定した対称性 - らせんパラメータ - Δz: 2.335 Å 想定した対称性 - らせんパラメータ - ΔΦ: -179.275 ° 想定した対称性 - らせんパラメータ - 軸対称性: C1 (非対称) 解像度のタイプ: BY AUTHOR / 解像度: 4.0 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア - 名称: SPARX (ver. 4.0) 詳細: For the even/odd test, the fibrils were split after the final reconstruction (no gold-standard). These two half sets were then refined further independently for another 12 iterations. 使用した粒子像数: 127765