ジャーナル: Nat Commun / 年: 2015 タイトル: Cryo-EM structure of the bacteriophage T4 portal protein assembly at near-atomic resolution. 著者: Lei Sun / Xinzheng Zhang / Song Gao / Prashant A Rao / Victor Padilla-Sanchez / Zhenguo Chen / Siyang Sun / Ye Xiang / Sriram Subramaniam / Venigalla B Rao / Michael G Rossmann / 要旨: The structure and assembly of bacteriophage T4 has been extensively studied. However, the detailed structure of the portal protein remained unknown. Here we report the structure of the bacteriophage ...The structure and assembly of bacteriophage T4 has been extensively studied. However, the detailed structure of the portal protein remained unknown. Here we report the structure of the bacteriophage T4 portal assembly, gene product 20 (gp20), determined by cryo-electron microscopy (cryo-EM) to 3.6 Å resolution. In addition, analysis of a 10 Å resolution cryo-EM map of an empty prolate T4 head shows how the dodecameric portal assembly interacts with the capsid protein gp23 at the special pentameric vertex. The gp20 structure also verifies that the portal assembly is required for initiating head assembly, for attachment of the packaging motor, and for participation in DNA packaging. Comparison of the Myoviridae T4 portal structure with the known portal structures of φ29, SPP1 and P22, representing Podo- and Siphoviridae, shows that the portal structure probably dates back to a time when self-replicating microorganisms were being established on Earth.
詳細: Quantifoil R1.2/1.3 holey carbon on 200 mesh copper
凍結
凍結剤: ETHANE / チャンバー内湿度: 90 % / チャンバー内温度: 120 K / 装置: GATAN CRYOPLUNGE 3 / 手法: Blot for 7 seconds before plunging
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
温度
最低: 80 K / 最高: 105 K / 平均: 100 K
特殊光学系
エネルギーフィルター - 名称: Gatan 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: 25.0 eV
日付
2014年7月10日
撮影
カテゴリ: CCD / フィルム・検出器のモデル: GATAN K2 (4k x 4k) / 実像数: 839 / 平均電子線量: 2 e/Å2 詳細: Every image is the average of 11 frames recorded by the direct electron detector. ビット/ピクセル: 8