Journal: Nucleic Acids Res / Year: 2024 Title: Structural basis for transcription activation by the nitrate-responsive regulator NarL. Authors: Dmytro Kompaniiets / Lina He / Dong Wang / Wei Zhou / Yang Yang / Yangbo Hu / Bin Liu / Abstract: Transcription activation is a crucial step of regulation during transcription initiation and a classic check point in response to different stimuli and stress factors. The Escherichia coli NarL is a ...Transcription activation is a crucial step of regulation during transcription initiation and a classic check point in response to different stimuli and stress factors. The Escherichia coli NarL is a nitrate-responsive global transcription factor that controls the expression of nearly 100 genes. However, the molecular mechanism of NarL-mediated transcription activation is not well defined. Here we present a cryo-EM structure of NarL-dependent transcription activation complex (TAC) assembled on the yeaR promoter at 3.2 Å resolution. Our structure shows that the NarL dimer binds at the -43.5 site of the promoter DNA with its C-terminal domain (CTD) not only binding to the DNA but also making interactions with RNA polymerase subunit alpha CTD (αCTD). The key role of these NarL-mediated interactions in transcription activation was further confirmed by in vivo and in vitro transcription assays. Additionally, the NarL dimer binds DNA in a different plane from that observed in the structure of class II TACs. Unlike the canonical class II activation mechanism, NarL does not interact with σ4, while RNAP αCTD is bound to DNA on the opposite side of NarL. Our findings provide a structural basis for detailed mechanistic understanding of NarL-dependent transcription activation on yeaR promoter and reveal a potentially novel mechanism of transcription activation.
Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 290 K / Instrument: FEI VITROBOT MARK IV
-
Electron microscopy
Microscope
FEI TITAN KRIOS
Temperature
Min: 77.0 K
Specialist optics
Energy filter - Name: GIF Bioquantum / Energy filter - Slit width: 20 eV
Image recording
Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Digitization - Dimensions - Width: 5769 pixel / Digitization - Dimensions - Height: 4092 pixel / Number grids imaged: 1 / Number real images: 8727 / Average exposure time: 2.0 sec. / Average electron dose: 42.0 e/Å2
Electron beam
Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN
In the structure databanks used in Yorodumi, some data are registered as the other names, "COVID-19 virus" and "2019-nCoV". Here are the details of the virus and the list of structure data.
Jan 31, 2019. EMDB accession codes are about to change! (news from PDBe EMDB page)
EMDB accession codes are about to change! (news from PDBe EMDB page)
The allocation of 4 digits for EMDB accession codes will soon come to an end. Whilst these codes will remain in use, new EMDB accession codes will include an additional digit and will expand incrementally as the available range of codes is exhausted. The current 4-digit format prefixed with “EMD-” (i.e. EMD-XXXX) will advance to a 5-digit format (i.e. EMD-XXXXX), and so on. It is currently estimated that the 4-digit codes will be depleted around Spring 2019, at which point the 5-digit format will come into force.
The EM Navigator/Yorodumi systems omit the EMD- prefix.
Related info.:Q: What is EMD? / ID/Accession-code notation in Yorodumi/EM Navigator
Yorodumi is a browser for structure data from EMDB, PDB, SASBDB, etc.
This page is also the successor to EM Navigator detail page, and also detail information page/front-end page for Omokage search.
The word "yorodu" (or yorozu) is an old Japanese word meaning "ten thousand". "mi" (miru) is to see.
Related info.:EMDB / PDB / SASBDB / Comparison of 3 databanks / Yorodumi Search / Aug 31, 2016. New EM Navigator & Yorodumi / Yorodumi Papers / Jmol/JSmol / Function and homology information / Changes in new EM Navigator and Yorodumi