8t02

Reconstituted E. coli RNA polymerase post-termination complex on negatively-supercoiled DNA: unwinding duplex DNA (rPTCi)

spinqualitylabelsall models 8t02, resolution 3.79Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8t02 is a 7 chain structure with sequence from Escherichia coli and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.79Å Ligands: 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 Following transcript release during intrinsic termination, Escherichia coli RNA polymerase (RNAP) often remains associated with DNA in a post-termination complex (PTC). RNAPs in PTCs are removed from the DNA by the SWI2/SNF2 adenosine triphosphatase (ATPase) RapA. Here we determined PTC structures on negatively supercoiled DNA and with RapA engaged to dislodge the PTC. We found that core RNAP in the PTC can unwind DNA and initiate RNA synthesis but is prone to producing R-loops. Nucleotide binding to RapA triggers a conformational change that opens the RNAP clamp, allowing DNA in the RNAP cleft to reanneal and dissociate. We show that RapA helps to control cytotoxic R-loop formation in vivo, likely by disrupting PTCs. We suggest that analogous ATPases acting on PTCs to suppress transcriptional noise and R-loop formation may be widespread. These results hold importance for the bacterial transcription cycle and highlight a role for RapA in maintaining genome stability. RapA opens the RNA polymerase clamp to disrupt post-termination complexes and prevent cytotoxic R-loop formation.,Brewer JJ, Inlow K, Mooney RA, Bosch B, Olinares PDB, Marcelino LP, Chait BT, Landick R, Gelles J, Campbell EA, Darst SA Nat Struct Mol Biol. 2025 Jan 8. doi: 10.1038/s41594-024-01447-8. PMID:39779919 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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