6rin

Cryo-EM structure of E. coli RNA polymerase backtracked elongation complex bound to GreB transcription factorCryo-EM structure of E. coli RNA polymerase backtracked elongation complex bound to GreB transcription factor

6rin, resolution 3.70Å Show:Asymmetric Unit Biological Assembly Structural highlights 6rin is a 9 chain structure with sequence from Escherichia coli and Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.7Å Ligands: Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GREB_ECOLI Necessary for efficient RNA polymerase transcription elongation past template-encoded arresting sites. The arresting sites in DNA have the property of trapping a certain fraction of elongating RNA polymerases that pass through, resulting in locked ternary complexes. Cleavage of the nascent transcript by cleavage factors such as GreA or GreB allows the resumption of elongation from the new 3'terminus. GreB releases sequences of up to 9 nucleotides in length.[HAMAP-Rule:MF_00930] Publication Abstract from PubMed Regulatory sequences or erroneous incorporations during DNA transcription cause RNA polymerase backtracking and inactivation in all kingdoms of life. Reactivation requires RNA transcript cleavage. Essential transcription factors (GreA and GreB, or TFIIS) accelerate this reaction. We report four cryo-EM reconstructions of Escherichia coli RNA polymerase representing the entire reaction pathway: (1) a backtracked complex; a backtracked complex with GreB (2) before and (3) after RNA cleavage; and (4) a reactivated, substrate-bound complex with GreB before RNA extension. Compared with eukaryotes, the backtracked RNA adopts a different conformation. RNA polymerase conformational changes cause distinct GreB states: a fully engaged GreB before cleavage; a disengaged GreB after cleavage; and a dislodged, loosely bound GreB removed from the active site to allow RNA extension. These reconstructions provide insight into the catalytic mechanism and dynamics of RNA cleavage and extension and suggest how GreB targets backtracked complexes without interfering with canonical transcription. Structural Basis of Transcription: RNA Polymerase Backtracking and Its Reactivation.,Abdelkareem M, Saint-Andre C, Takacs M, Papai G, Crucifix C, Guo X, Ortiz J, Weixlbaumer A Mol Cell. 2019 May 8. pii: S1097-2765(19)30321-1. doi:, 10.1016/j.molcel.2019.04.029. PMID:31103420 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Elongation factor 3D structures RNA polymerase 3D structures