7UBJ

Transcription antitermination factor Qlambda, type-I crystal

7UBJ の概要

• エントリーDOI: 10.2210/pdb7ubj/pdb
• 分子名称: Antitermination protein Q, ZINC ION, CHLORIDE ION, ... (8 entities in total)
• 機能のキーワード: rna polymerase, dna binding, transcription, q-dependent antitermination, q antitermination factor, gene regulation
• 由来する生物種: Escherichia phage Lambda
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 33590.70

構造登録者

Yin, Z.,Ebright, R.H. (登録日: 2022-03-15, 公開日: 2022-09-28, 最終更新日: 2023-10-18)

主引用文献

Yin, Z.,Bird, J.G.,Kaelber, J.T.,Nickels, B.E.,Ebright, R.H.
In transcription antitermination by Q lambda , NusA induces refolding of Q lambda to form a nozzle that extends the RNA polymerase RNA-exit channel.
Proc.Natl.Acad.Sci.USA, 119:e2205278119-e2205278119, 2022

PubMed Abstract: Lambdoid bacteriophage Q proteins are transcription antipausing and antitermination factors that enable RNA polymerase (RNAP) to read through pause and termination sites. Q proteins load onto RNAP engaged in promoter-proximal pausing at a Q binding element (QBE) and adjacent sigma-dependent pause element to yield a Q-loading complex, and they translocate with RNAP as a pausing-deficient, termination-deficient Q-loaded complex. In previous work, we showed that the Q protein of bacteriophage 21 (Q21) functions by forming a nozzle that narrows and extends the RNAP RNA-exit channel, preventing formation of pause and termination RNA hairpins. Here, we report atomic structures of four states on the pathway of antitermination by the Q protein of bacteriophage λ (Qλ), a Q protein that shows no sequence similarity to Q21 and that, unlike Q21, requires the transcription elongation factor NusA for efficient antipausing and antitermination. We report structures of Qλ, the Qλ-QBE complex, the NusA-free pre-engaged Qλ-loading complex, and the NusA-containing engaged Qλ-loading complex. The results show that Qλ, like Q21, forms a nozzle that narrows and extends the RNAP RNA-exit channel, preventing formation of RNA hairpins. However, the results show that Qλ has no three-dimensional structural similarity to Q21, employs a different mechanism of QBE recognition than Q21, and employs a more complex process for loading onto RNAP than Q21, involving recruitment of Qλ to form a pre-engaged loading complex, followed by NusA-facilitated refolding of Qλ to form an engaged loading complex. The results establish that Qλ and Q21 are not structural homologs and are solely functional analogs.

PubMed: 35951650
DOI: 10.1073/pnas.2205278119

実験手法

X-RAY DIFFRACTION (1.46 Å)