ジャーナル: Nature / 年: 2016 タイトル: Structure of transcribing mammalian RNA polymerase II. 著者: Carrie Bernecky / Franz Herzog / Wolfgang Baumeister / Jürgen M Plitzko / Patrick Cramer / 要旨: RNA polymerase (Pol) II produces messenger RNA during transcription of protein-coding genes in all eukaryotic cells. The Pol II structure is known at high resolution from X-ray crystallography for ...RNA polymerase (Pol) II produces messenger RNA during transcription of protein-coding genes in all eukaryotic cells. The Pol II structure is known at high resolution from X-ray crystallography for two yeast species. Structural studies of mammalian Pol II, however, remain limited to low-resolution electron microscopy analysis of human Pol II and its complexes with various proteins. Here we report the 3.4 Å resolution cryo-electron microscopy structure of mammalian Pol II in the form of a transcribing complex comprising DNA template and RNA transcript. We use bovine Pol II, which is identical to the human enzyme except for seven amino-acid residues. The obtained atomic model closely resembles its yeast counterpart, but also reveals unknown features. Binding of nucleic acids to the polymerase involves 'induced fit' of the mobile Pol II clamp and active centre region. DNA downstream of the transcription bubble contacts a conserved 'TPSA motif' in the jaw domain of the Pol II subunit RPB5, an interaction that is apparently already established during transcription initiation. Upstream DNA emanates from the active centre cleft at an angle of approximately 105° with respect to downstream DNA. This position of upstream DNA allows for binding of the general transcription elongation factor DSIF (SPT4-SPT5) that we localize over the active centre cleft in a conserved position on the clamp domain of Pol II. Our results define the structure of mammalian Pol II in its functional state, indicate that previous crystallographic analysis of yeast Pol II is relevant for understanding gene transcription in all eukaryotes, and provide a starting point for a mechanistic analysis of human transcription.
タンパク質・ペプチド: DNA-directed RNA polymerase II subunit GRINL1A
Other: DNA-RNA synthetic construct
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超分子 #1000: bovine Pol II elongation complex
超分子
名称: bovine Pol II elongation complex / タイプ: sample / ID: 1000 詳細: Recombinant human Gdown1 was present during sample preparation but density was not observed in this map. Number unique components: 3
分子量
理論値: 590 KDa
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分子 #1: DNA-directed RNA polymerase II
分子
名称: DNA-directed RNA polymerase II / タイプ: protein_or_peptide / ID: 1 / Name.synonym: RNA polymerase II / コピー数: 1 / 集合状態: Monomer / 組換発現: No
由来(天然)
生物種: Bos taurus (ウシ) / 別称: Cow / 組織: Thymus
分子量
理論値: 520 KDa
配列
GO: DNA-directed RNA polymerase activity
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分子 #2: DNA-directed RNA polymerase II subunit GRINL1A
pH: 7.25 / 詳細: 150 mM NaCl, 5 mM HEPES, 0.01 mM ZnCl2, 10 mM DTT
グリッド
詳細: Quantifoil R 3.5/1 holey carbon grids
凍結
凍結剤: ETHANE / チャンバー内湿度: 100 % / 装置: FEI VITROBOT MARK IV 手法: Four microliters of sample was applied to glow-discharged Quantifoil R 3.5/1 holey carbon grids, which were then blotted for 8.5s and plunge-frozen in liquid ethane.
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
特殊光学系
エネルギーフィルター - 名称: GIF Quantum 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: 20.0 eV
日付
2014年12月1日
撮影
カテゴリ: CCD フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) 実像数: 1172 / 平均電子線量: 43 e/Å2 詳細: Each movie image was collected over 8 s fractionated into 40 frames (0.2 s each).