12ec | pdb_000012ec

Half-translocated RNA polymerase elemental paused elongation complex, swiveled (ePEC swiveled)

spinqualitylabelsall models 12ec, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 12ec is a 8 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.6Å Ligands: 1N7, MG, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RPOA_ECOLI DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit plays an important role in subunit assembly since its dimerization is the first step in the sequential assembly of subunits to form the holoenzyme.[HAMAP-Rule:MF_00059] Publication Abstract from PubMed The signaling molecules guanosine 5'-tri/diphosphate 3'-diphosphate, (p)ppGpp, control bacterial protein synthesis rates and cell growth by targeting transcription, translation, NTP synthesis, and other functions. In lineages like E. coli, (p)ppGpp produced in response to charged-tRNA deficiency directly targets transcribing RNAP polymerase (RNAP) to match its pace to the pioneering ribosome on the nascent RNA (transcription-translation coupling). However, the mechanism by which (p)ppGpp slows RNAP is poorly defined. (p)ppGpp may allosterically stimulate RNAP pausing, inhibit catalysis, promote backtracking, compete for substrate GTP, inhibit GTP synthesis, or uncouple transcription-translation by inhibiting translation. Using a combination of cryo-EM, biochemical assays, and quantitative nascent elongating transcript sequencing (qNET-seq), we establish that (p)ppGpp allosterically regulates pausing and nucleotide addition via distinct motions of the RNAP swivel module and both competes with and lowers GTP in vivo. (p)ppGpp stimulates swiveling at pause sites to delay escape but may also inhibit counter-swiveling required in every round of nucleotide addition. ppGpp regulates transcription elongation via direct and indirect inputs to RNA polymerase pausing and nucleotide addition.,Mueller AU, Mooney RA, Engstrom MD, Bao Y, Wolfe MB, Sah B, Buscher J, Saba J, Liu J, Darst SA, Landick R bioRxiv [Preprint]. 2026 May 14:2026.05.13.724835. doi: , 10.64898/2026.05.13.724835. PMID:42182161 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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