ジャーナル: Sci Adv / 年: 2022 タイトル: The pore conformation of lymphocyte perforin. 著者: Marina E Ivanova / Natalya Lukoyanova / Sony Malhotra / Maya Topf / Joseph A Trapani / Ilia Voskoboinik / Helen R Saibil / 要旨: Perforin is a pore-forming protein that facilitates rapid killing of pathogen-infected or cancerous cells by the immune system. Perforin is released from cytotoxic lymphocytes, together with ...Perforin is a pore-forming protein that facilitates rapid killing of pathogen-infected or cancerous cells by the immune system. Perforin is released from cytotoxic lymphocytes, together with proapoptotic granzymes, to bind to a target cell membrane where it oligomerizes and forms pores. The pores allow granzyme entry, which rapidly triggers the apoptotic death of the target cell. Here, we present a 4-Å resolution cryo-electron microscopy structure of the perforin pore, revealing previously unidentified inter- and intramolecular interactions stabilizing the assembly. During pore formation, the helix-turn-helix motif moves away from the bend in the central β sheet to form an intermolecular contact. Cryo-electron tomography shows that prepores form on the membrane surface with minimal conformational changes. Our findings suggest the sequence of conformational changes underlying oligomerization and membrane insertion, and explain how several pathogenic mutations affect function.
フィルム・検出器のモデル: GATAN K3 BIOQUANTUM (6k x 4k) 平均電子線量: 49.6 e/Å2
電子線
加速電圧: 300 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
実験機器
モデル: Titan Krios / 画像提供: FEI Company
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画像解析
初期モデル
モデルのタイプ: OTHER
最終 再構成
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 詳細: 229,789 particles were symmetry expanded with C22 symmetry giving the final number of particles 5,055,358 使用した粒子像数: 229789