ジャーナル: Nat Commun / 年: 2024 タイトル: Sm-like protein Rof inhibits transcription termination factor ρ by binding site obstruction and conformational insulation. 著者: Nelly Said / Mark Finazzo / Tarek Hilal / Bing Wang / Tim Luca Selinger / Daniela Gjorgjevikj / Irina Artsimovitch / Markus C Wahl / 要旨: Transcription termination factor ρ is a hexameric, RNA-dependent NTPase that can adopt active closed-ring and inactive open-ring conformations. The Sm-like protein Rof, a homolog of the RNA ...Transcription termination factor ρ is a hexameric, RNA-dependent NTPase that can adopt active closed-ring and inactive open-ring conformations. The Sm-like protein Rof, a homolog of the RNA chaperone Hfq, inhibits ρ-dependent termination in vivo but recapitulation of this activity in vitro has proven difficult and the precise mode of Rof action is presently unknown. Here, our cryo-EM structures of ρ-Rof and ρ-RNA complexes show that Rof undergoes pronounced conformational changes to bind ρ at the protomer interfaces, undercutting ρ conformational dynamics associated with ring closure and occluding extended primary RNA-binding sites that are also part of interfaces between ρ and RNA polymerase. Consistently, Rof impedes ρ ring closure, ρ-RNA interactions and ρ association with transcription elongation complexes. Structure-guided mutagenesis coupled with functional assays confirms that the observed ρ-Rof interface is required for Rof-mediated inhibition of cell growth and ρ-termination in vitro. Bioinformatic analyses reveal that Rof is restricted to Pseudomonadota and that the ρ-Rof interface is conserved. Genomic contexts of rof differ between Enterobacteriaceae and Vibrionaceae, suggesting distinct modes of Rof regulation. We hypothesize that Rof and other cellular anti-terminators silence ρ under diverse, but yet to be identified, stress conditions when unrestrained transcription termination by ρ may be detrimental.
タイプ: RANDOM ASSIGNMENT / ソフトウェア - 名称: cryoSPARC (ver. 3.3.1)
最終 角度割当
タイプ: MAXIMUM LIKELIHOOD / ソフトウェア - 名称: cryoSPARC (ver. 3.3.1)
最終 3次元分類
ソフトウェア - 名称: cryoSPARC (ver. 3.3.1)
FSC曲線 (解像度の算出)
-
原子モデル構築 1
初期モデル
Chain - Chain ID: A / Chain - Residue range: 1-419 / Chain - Source name: Other / Chain - Initial model type: experimental model / 詳細: own experimental data
精密化
空間: REAL / プロトコル: RIGID BODY FIT / 温度因子: 98
得られたモデル
PDB-8ptn: Structure of the transcription termination factor Rho in complex with Rof