ジャーナル: Elife / 年: 2017 タイトル: Cryo-EM structure of the SAGA and NuA4 coactivator subunit Tra1 at 3.7 angstrom resolution. 著者: Luis Miguel Díaz-Santín / Natasha Lukoyanova / Emir Aciyan / Alan Cm Cheung / 要旨: Coactivator complexes SAGA and NuA4 stimulate transcription by post-translationally modifying chromatin. Both complexes contain the Tra1 subunit, a highly conserved 3744-residue protein from the ...Coactivator complexes SAGA and NuA4 stimulate transcription by post-translationally modifying chromatin. Both complexes contain the Tra1 subunit, a highly conserved 3744-residue protein from the Phosphoinositide 3-Kinase-related kinase (PIKK) family and a direct target for multiple sequence-specific activators. We present the Cryo-EM structure of Tra1 to 3.7 Å resolution, revealing an extensive network of alpha-helical solenoids organized into a diamond ring conformation and is strikingly reminiscent of DNA-PKcs, suggesting a direct role for Tra1 in DNA repair. The structure was fitted into an existing SAGA EM reconstruction and reveals limited contact surfaces to Tra1, hence it does not act as a molecular scaffold within SAGA. Mutations that affect activator targeting are distributed across the Tra1 structure, but also cluster within the N-terminal Finger region, indicating the presence of an activator interaction site. The structure of Tra1 is a key milestone in deciphering the mechanism of multiple coactivator complexes.
濃度: 0.1 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES
試料支持
グリッドのタイプ: Agar Scientific
急速凍結
装置: FEI VITROBOT MARK IV / 凍結剤: ETHANE / 湿度: 94 % / 凍結前の試料温度: 277 K 詳細: Two subsequent applications of protein were required to achieve the desired particle density on grids. Each application was followed by 20 sec waiting time, with a short 0.5 sec blotting ...詳細: Two subsequent applications of protein were required to achieve the desired particle density on grids. Each application was followed by 20 sec waiting time, with a short 0.5 sec blotting after first application and 5 sec blotting after the second.
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電子顕微鏡撮影
実験機器
モデル: Titan Krios / 画像提供: FEI Company
顕微鏡
モデル: FEI TITAN KRIOS
電子銃
電子線源: FIELD EMISSION GUN / 加速電圧: 300 kV / 照射モード: OTHER
電子レンズ
モード: OTHER / 最大 デフォーカス(公称値): 3500 nm / 最小 デフォーカス(公称値): 1500 nm / Cs: 2.7 mm