ジャーナル: PLoS Pathog / 年: 2016 タイトル: Acidic pH-Induced Conformations and LAMP1 Binding of the Lassa Virus Glycoprotein Spike. 著者: Sai Li / Zhaoyang Sun / Rhys Pryce / Marie-Laure Parsy / Sarah K Fehling / Katrin Schlie / C Alistair Siebert / Wolfgang Garten / Thomas A Bowden / Thomas Strecker / Juha T Huiskonen / 要旨: Lassa virus is an enveloped, bi-segmented RNA virus and the most prevalent and fatal of all Old World arenaviruses. Virus entry into the host cell is mediated by a tripartite surface spike complex, ...Lassa virus is an enveloped, bi-segmented RNA virus and the most prevalent and fatal of all Old World arenaviruses. Virus entry into the host cell is mediated by a tripartite surface spike complex, which is composed of two viral glycoprotein subunits, GP1 and GP2, and the stable signal peptide. Of these, GP1 binds to cellular receptors and GP2 catalyzes fusion between the viral envelope and the host cell membrane during endocytosis. The molecular structure of the spike and conformational rearrangements induced by low pH, prior to fusion, remain poorly understood. Here, we analyzed the three-dimensional ultrastructure of Lassa virus using electron cryotomography. Sub-tomogram averaging yielded a structure of the glycoprotein spike at 14-Å resolution. The spikes are trimeric, cover the virion envelope, and connect to the underlying matrix. Structural changes to the spike, following acidification, support a viral entry mechanism dependent on binding to the lysosome-resident receptor LAMP1 and further dissociation of the membrane-distal GP1 subunits.
詳細: Grids (Cflat CF-2/1-2C-T) were glow-discharged 15 s. 6-nm gold particles were added.
凍結
凍結剤: ETHANE-PROPANE MIXTURE / チャンバー内湿度: 80 % / チャンバー内温度: 120 K / 装置: GATAN CRYOPLUNGE 3 / 手法: Blot for 3 seconds before plunging.
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電子顕微鏡法
顕微鏡
FEI POLARA 300
温度
最低: 80 K / 最高: 120 K
アライメント法
Legacy - 非点収差: Objective lens astigmatism was corrected at 160,000 times magnification.
特殊光学系
エネルギーフィルター - 名称: GIF QUANTUM LS エネルギーフィルター - エネルギー下限: 0.0 eV エネルギーフィルター - エネルギー上限: 20.0 eV
詳細
Super-resolution counting mode
日付
2014年6月18日
撮影
カテゴリ: CCD フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) デジタル化 - サンプリング間隔: 5 µm / 実像数: 27 / 平均電子線量: 60 e/Å2 詳細: Each image is a tilt series of 19 movies, acquired at 5 degree intervals. Each movie consists of 8 frames.