Netherlands Organisation for Scientific Research (NWO)
184.034.014
オランダ
引用
ジャーナル: J Struct Biol / 年: 2021 タイトル: Structure of the Yersinia injectisome in intracellular host cell phagosomes revealed by cryo FIB electron tomography. 著者: Casper Berger / Raimond B G Ravelli / Carmen López-Iglesias / Mikhail Kudryashev / Andreas Diepold / Peter J Peters / 要旨: Many pathogenic bacteria use the type III secretion system (T3SS), or injectisome, to secrete toxins into host cells. These protruding systems are primary targets for drug and vaccine development. ...Many pathogenic bacteria use the type III secretion system (T3SS), or injectisome, to secrete toxins into host cells. These protruding systems are primary targets for drug and vaccine development. Upon contact between injectisomes and host membranes, toxin secretion is triggered. How this works structurally and functionally is yet unknown. Using cryo-focused ion beam milling and cryo-electron tomography, we visualized injectisomes of Yersinia enterocolitica inside the phagosomes of infected human myeloid cells in a close-to-native state. We observed that a minimum needle length is required for injectisomes to contact the host membrane and bending of host membranes by some injectisomes that contact the host. Through subtomogram averaging, the structure of the entire injectisome was determined, which revealed structural differences in the cytosolic sorting platform compared to other bacteria. These findings contribute to understanding how injectisomes secrete toxins into host cells and provides the indispensable native context. The application of these cryo-electron microscopy techniques paves the way for the study of the 3D structure of infection-relevant protein complexes in host-pathogen interactions.
Subtomogram average structure of the type III secretion system of yersinia enterocolitica - focused on the basal body and filtered to 3.3 nm resolution.
凍結剤: ETHANE / チャンバー内湿度: 85 % / チャンバー内温度: 310 K / 装置: HOMEMADE PLUNGER 詳細: FEI vitrobot modified with a jet-vitrification module and a blotforce feedback mechanism..
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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: COUNTING / 平均露光時間: 24.0 sec. / 平均電子線量: 2.86 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 / 最小 デフォーカス(公称値): -0.005 µm
試料ステージ
ホルダー冷却材: NITROGEN
実験機器
モデル: Talos Arctica / 画像提供: FEI Company
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画像解析
詳細
Tilt-series aligned and reconstructed with IMOD with gold fiducials.
最終 再構成
想定した対称性 - 点群: C3 (3回回転対称) / 解像度のタイプ: BY AUTHOR / 解像度: 33.0 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア - 名称: Dynamo (ver. 1.1.401) / 使用したサブトモグラム数: 141
抽出
トモグラム数: 63 / 使用した粒子像数: 202 / 参照モデル: averaged from data after manual alignment / 手法: manually picked / ソフトウェア - 名称: Dynamo (ver. 1.1.401) 詳細: 4x binned tomograms were filtered with EMDeconvolution for manual picking. Coordinates were transformed to extract particles from 2x binned tomograms after CTF correction and without filtering.
CTF補正
ソフトウェア - 名称: IMOD (ver. 4) / 詳細: CTF correction performed with IMOD
最終 角度割当
タイプ: NOT APPLICABLE / ソフトウェア - 名称: Dynamo (ver. 1.1.401)