8f3c | pdb_00008f3c

Cryo-EM consensus structure of Escherichia coli que-PEC (paused elongation complex) RNA Polymerase minus preQ1 ligand

spinqualitylabelsall models 8f3c, resolution 3.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8f3c 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. Ligands: MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RPOA_ECOK1 DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Publication Abstract from PubMed Folding of nascent transcripts can be modulated by the RNA polymerase (RNAP) that carries out their transcription, and vice versa. A pause of RNAP during transcription of a preQ(1) riboswitch (termed que-PEC) is stabilized by a previously characterized template consensus sequence and the ligand-free conformation of the nascent RNA. Ligand binding to the riboswitch induces RNAP pause release and downstream transcription termination; however, the mechanism by which riboswitch folding modulates pausing is unclear. Here, we report single-particle cryo-electron microscopy reconstructions of que-PEC in ligand-free and ligand-bound states. In the absence of preQ(1), the RNA transcript is in an unexpected hyper-translocated state, preventing downstream nucleotide incorporation. Strikingly, on ligand binding, the riboswitch rotates around its helical axis, expanding the surrounding RNAP exit channel and repositioning the transcript for elongation. Our study reveals the tight coupling by which nascent RNA structures and their ligands can functionally regulate the macromolecular transcription machinery. Structural basis for control of bacterial RNA polymerase pausing by a riboswitch and its ligand.,Chauvier A, Porta JC, Deb I, Ellinger E, Meze K, Frank AT, Ohi MD, Walter NG Nat Struct Mol Biol. 2023 Jun 1. doi: 10.1038/s41594-023-01002-x. PMID:37264140 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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