ジャーナル: Proc Natl Acad Sci U S A / 年: 2007 タイトル: Architecture of the yeast Rrp44 exosome complex suggests routes of RNA recruitment for 3' end processing. 著者: Hong-Wei Wang / Jianjun Wang / Fang Ding / Kevin Callahan / Matthew A Bratkowski / J Scott Butler / Eva Nogales / Ailong Ke / 要旨: The eukaryotic core exosome (CE) is a conserved nine-subunit protein complex important for 3' end trimming and degradation of RNA. In yeast, the Rrp44 protein constitutively associates with the CE ...The eukaryotic core exosome (CE) is a conserved nine-subunit protein complex important for 3' end trimming and degradation of RNA. In yeast, the Rrp44 protein constitutively associates with the CE and provides the sole source of processive 3'-to-5' exoribonuclease activity. Here we present EM reconstructions of the core and Rrp44-bound exosome complexes. The two-lobed Rrp44 protein binds to the RNase PH domain side of the exosome and buttresses the bottom of the exosome-processing chamber. The Rrp44 C-terminal body part containing an RNase II-type active site is anchored to the exosome through a conserved set of interactions mainly to the Rrp45 and Rrp43 subunit, whereas the Rrp44 N-terminal head part is anchored to the Rrp41 subunit and may function as a roadblock to restrict access of RNA to the active site in the body region. The Rrp44-exosome (RE) architecture suggests an active site sequestration mechanism for strict control of 3' exoribonuclease activity in the RE complex.
pH: 7.5 詳細: 25 mM Tris-HCl, 50 mM NaCl, 2 mM DTT, and 10 uM ZnCl2
染色
タイプ: NEGATIVE 詳細: Four microliters of the protein solution was negatively stained with 2% uranyl formate solution between two thin layers of carbon on a copper grid by using the sandwich method.
グリッド
詳細: 400 mesh copper grid
凍結
凍結剤: ETHANE
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電子顕微鏡法
顕微鏡
FEI TECNAI 12
温度
平均: 300 K
アライメント法
Legacy - 非点収差: objective lens astigmatism was corrected at 100,000 times magnification
詳細
Low dose mode was used for taking pictures
日付
2006年8月1日
撮影
カテゴリ: FILM / フィルム・検出器のモデル: KODAK SO-163 FILM / デジタル化 - スキャナー: OTHER / デジタル化 - サンプリング間隔: 12.7 µm / 実像数: 50 / 平均電子線量: 20 e/Å2 詳細: The micrographs were scanned on a Nikon Super Coolscan 8000 scanner Od range: 1.4 / ビット/ピクセル: 14
試料ホルダー: normal single-tilt holder / 試料ホルダーモデル: OTHER
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画像解析
最終 再構成
想定した対称性 - 点群: C1 (非対称) / アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 23.0 Å / 解像度の算出法: FSC 0.5 CUT-OFF / ソフトウェア - 名称: SPIDER / 詳細: Final map were calculated from all the particles. / 使用した粒子像数: 2980