ジャーナル: Proc Natl Acad Sci U S A / 年: 2011 タイトル: Structure of Trypanosoma brucei flagellum accounts for its bihelical motion. 著者: Alexey Y Koyfman / Michael F Schmid / Ladan Gheiratmand / Caroline J Fu / Htet A Khant / Dandan Huang / Cynthia Y He / Wah Chiu / 要旨: Trypanosoma brucei is a parasitic protozoan that causes African sleeping sickness. It contains a flagellum required for locomotion and viability. In addition to a microtubular axoneme, the flagellum ...Trypanosoma brucei is a parasitic protozoan that causes African sleeping sickness. It contains a flagellum required for locomotion and viability. In addition to a microtubular axoneme, the flagellum contains a crystalline paraflagellar rod (PFR) and connecting proteins. We show here, by cryoelectron tomography, the structure of the flagellum in three bending states. The PFR lattice in straight flagella repeats every 56 nm along the length of the axoneme, matching the spacing of the connecting proteins. During flagellar bending, the PFR crystallographic unit cell lengths remain constant while the interaxial angles vary, similar to a jackscrew. The axoneme drives the expansion and compression of the PFR lattice. We propose that the PFR modifies the in-plane axoneme motion to produce the characteristic trypanosome bihelical motility as captured by high-speed light microscope videography.
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 100 K / 装置: FEI VITROBOT MARK III / 詳細: Vitrification instrument: Vitrobot III / 手法: Blot for 2 seconds before plunging
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電子顕微鏡法
顕微鏡
JEOL 2100
日付
2008年6月25日
撮影
平均電子線量: 70 e/Å2
電子線
加速電圧: 200 kV / 電子線源: LAB6
電子光学系
照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELD / 倍率(公称値): 15000
試料ステージ
試料ホルダー: 60 degree / 試料ホルダーモデル: GATAN LIQUID NITROGEN / Tilt series - Axis1 - Min angle: -60 ° / Tilt series - Axis1 - Max angle: 60 °
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画像解析
詳細
Average number of tilts used in the 3D reconstructions: 60. Average tomographic tilt angle increment: 2.