ジャーナル: Science / 年: 2016 タイトル: Structure of the Sec61 channel opened by a signal sequence. 著者: Rebecca M Voorhees / Ramanujan S Hegde / 要旨: Secreted and integral membrane proteins compose up to one-third of the biological proteome. These proteins contain hydrophobic signals that direct their translocation across or insertion into the ...Secreted and integral membrane proteins compose up to one-third of the biological proteome. These proteins contain hydrophobic signals that direct their translocation across or insertion into the lipid bilayer by the Sec61 protein-conducting channel. The molecular basis of how hydrophobic signals within a nascent polypeptide trigger channel opening is not understood. Here, we used cryo-electron microscopy to determine the structure of an active Sec61 channel that has been opened by a signal sequence. The signal supplants helix 2 of Sec61α, which triggers a rotation that opens the central pore both axially across the membrane and laterally toward the lipid bilayer. Comparisons with structures of Sec61 in other states suggest a pathway for how hydrophobic signals engage the channel to gain access to the lipid bilayer.
全体 : The stalled mammalian Sec61 complex opened by the pre-prolactin s...
全体
名称: The stalled mammalian Sec61 complex opened by the pre-prolactin signal sequence.
要素
試料: The stalled mammalian Sec61 complex opened by the pre-prolactin signal sequence.
複合体: mammalian ribosome
タンパク質・ペプチド: Sec61 channel
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超分子 #1000: The stalled mammalian Sec61 complex opened by the pre-prolactin s...
超分子
名称: The stalled mammalian Sec61 complex opened by the pre-prolactin signal sequence. タイプ: sample / ID: 1000 / 詳細: The sample was monodisperse / 集合状態: monomer / Number unique components: 2
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超分子 #1: mammalian ribosome
超分子
名称: mammalian ribosome / タイプ: complex / ID: 1 / Name.synonym: 80S ribosome / 組換発現: No / Ribosome-details: ribosome-eukaryote: ALL
pH: 7.5 詳細: 50 mM HEPES pH 7.5, 200 mM KOAc, 15 mM MgOAc2, 1 mM DTT, 0.25% digitonin
グリッド
詳細: 400 mesh holey carbon grid coated with a continuous layer of amorphous carbon
凍結
凍結剤: ETHANE / チャンバー内湿度: 100 % / 装置: FEI VITROBOT MARK II 手法: Incubate for 30 seconds at 4 C and blot for 9 seconds before plunging
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
アライメント法
Legacy - 非点収差: Objective astigmatism was corrected at 60,000 times magnification
日付
2015年3月9日
撮影
カテゴリ: CCD フィルム・検出器のモデル: FEI FALCON II (4k x 4k) 実像数: 1489 / 平均電子線量: 27 e/Å2 詳細: Every image is the average of 17 frames recorded by the direct electron detector.