ジャーナル: Nat Commun / 年: 2024 タイトル: Transient disome complex formation in native polysomes during ongoing protein synthesis captured by cryo-EM. 著者: Timo Flügel / Magdalena Schacherl / Anett Unbehaun / Birgit Schroeer / Marylena Dabrowski / Jörg Bürger / Thorsten Mielke / Thiemo Sprink / Christoph A Diebolder / Yollete V Guillén ...著者: Timo Flügel / Magdalena Schacherl / Anett Unbehaun / Birgit Schroeer / Marylena Dabrowski / Jörg Bürger / Thorsten Mielke / Thiemo Sprink / Christoph A Diebolder / Yollete V Guillén Schlippe / Christian M T Spahn / 要旨: Structural studies of translating ribosomes traditionally rely on in vitro assembly and stalling of ribosomes in defined states. To comprehensively visualize bacterial translation, we reactivated ex ...Structural studies of translating ribosomes traditionally rely on in vitro assembly and stalling of ribosomes in defined states. To comprehensively visualize bacterial translation, we reactivated ex vivo-derived E. coli polysomes in the PURE in vitro translation system and analyzed the actively elongating polysomes by cryo-EM. We find that 31% of 70S ribosomes assemble into disome complexes that represent eight distinct functional states including decoding and termination intermediates, and a pre-nucleophilic attack state. The functional diversity of disome complexes together with RNase digest experiments suggests that paused disome complexes transiently form during ongoing elongation. Structural analysis revealed five disome interfaces between leading and queueing ribosomes that undergo rearrangements as the leading ribosome traverses through the elongation cycle. Our findings reveal at the molecular level how bL9's CTD obstructs the factor binding site of queueing ribosomes to thwart harmful collisions and illustrate how translation dynamics reshape inter-ribosomal contacts.
凍結剤: ETHANE / チャンバー内湿度: 75 % / チャンバー内温度: 277 K / 装置: FEI VITROBOT MARK IV 詳細: Withdrawn samples were spotted directly onto freshly glow-discharged holey carbon grids, blotted for 1-2 s, and flash frozen in liquid ethane using a Vitrobot Mark IV plunger (ThermoFisher ...詳細: Withdrawn samples were spotted directly onto freshly glow-discharged holey carbon grids, blotted for 1-2 s, and flash frozen in liquid ethane using a Vitrobot Mark IV plunger (ThermoFisher Scientific) after a wait time of 40 s at 4 degrees Celcius..
詳細
In vitro translation reactions were performed in the PURE translation system using the PURExpress delta ribosome kit (NEB, #E3313S). Translation reactions were supplemented with 0.8 U/uL RNAsin Plus RNase Inhibitor (Promega, N261B). SolA, factor mix, and RNAsin Plus were combined on ice, followed by a preincubation at 37 degrees Celcius for 2 min, and added directly to polysomes (700 nM final concentration) that had been preincubated at 37 degrees Celsius for 2 min. After 1 min reaction time, 4 uL of the reaction mixture were withdrawn for plunge freezing.
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
温度
最低: 80.0 K / 最高: 82.0 K
ソフトウェア
名称: EPU (ver. 2.8.1)
撮影
フィルム・検出器のモデル: GATAN K3 BIOQUANTUM (6k x 4k) 撮影したグリッド数: 1 / 実像数: 8982 / 平均露光時間: 1.13 sec. / 平均電子線量: 45.0 e/Å2