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Open data
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Basic information
Entry | Database: PDB / ID: 7ubk | ||||||
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Title | Transcription antitermination factor Qlambda, type-II crystal | ||||||
![]() | Antitermination protein Q | ||||||
![]() | GENE REGULATION / RNA polymerase / DNA Binding / transcription / Q-dependent antitermination / Q antitermination factor | ||||||
Function / homology | ![]() transcription antitermination / DNA-templated transcription termination / DNA binding / zinc ion binding Similarity search - Function | ||||||
Biological species | ![]() | ||||||
Method | ![]() ![]() ![]() ![]() | ||||||
![]() | Yin, Z. / Ebright, R.H. | ||||||
Funding support | ![]()
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![]() | ![]() Title: In transcription antitermination by Qλ, NusA induces refolding of Qλ to form a nozzle that extends the RNA polymerase RNA-exit channel. Authors: Zhou Yin / Jeremy G Bird / Jason T Kaelber / Bryce E Nickels / Richard H Ebright / ![]() 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 ...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. | ||||||
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-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 7ubjC ![]() 7ublC ![]() 7ubmC ![]() 7ubnC ![]() 4mo1S S: Starting model for refinement C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Assembly
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Noncrystallographic symmetry (NCS) | NCS domain:
NCS domain segments: Ens-ID: 1
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