National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35 GM118130
米国
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2023 タイトル: A general mechanism for transcription bubble nucleation in bacteria. 著者: Andreas U Mueller / James Chen / Mengyu Wu / Courtney Chiu / B Tracy Nixon / Elizabeth A Campbell / Seth A Darst / 要旨: Bacterial transcription initiation requires σ factors for nucleation of the transcription bubble. The canonical housekeeping σ factor, σ, nucleates DNA melting via recognition of conserved bases ...Bacterial transcription initiation requires σ factors for nucleation of the transcription bubble. The canonical housekeeping σ factor, σ, nucleates DNA melting via recognition of conserved bases of the promoter -10 motif, which are unstacked and captured in pockets of σ. By contrast, the mechanism of transcription bubble nucleation and formation during the unrelated σ-mediated transcription initiation is poorly understood. Herein, we combine structural and biochemical approaches to establish that σ, like σ, captures a flipped, unstacked base in a pocket formed between its N-terminal region I (RI) and extra-long helix features. Strikingly, RI inserts into the nascent bubble to stabilize the nucleated bubble prior to engagement of the obligate ATPase activator. Our data suggest a general paradigm of transcription initiation that requires σ factors to nucleate an early melted intermediate prior to productive RNA synthesis.
モデル: C-flat-1.2/1.3 / 材質: GOLD / メッシュ: 400 / 支持フィルム - 材質: CARBON / 支持フィルム - トポロジー: HOLEY / 前処理 - タイプ: GLOW DISCHARGE / 前処理 - 時間: 25 sec. / 前処理 - 雰囲気: AIR 詳細: Self-built glow discharge chamber was evacuated with a vacuum pump prior to application of voltage (no pressure and/or voltage readings available)
凍結
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 295 K / 装置: FEI VITROBOT MARK IV 詳細: Octyl beta-D-glucopyranoside (beta-OG) was added to the sample to 0.1%w/v final concentration (from 10x stock) just prior to plunge vitrification.