5tjg

Thermus aquaticus delta1.1-sigmaA holoenzyme/downstream-fork promoter complex with an open clamp

spinqualitylabelsall models 5tjg, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5tjg is a 7 chain structure with sequence from Escherichia coli and Thermus aquaticus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.6Å Ligands: MG, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RPOA_THEAQ Publication Abstract from PubMed All cellular RNA polymerases (RNAPs), from those of bacteria to those of man, possess a clamp that can open and close, and it has been assumed that the open RNAP separates promoter DNA strands and then closes to establish a tight grip on the DNA template. Here, we resolve successive motions of the initiating bacterial RNAP by studying real-time signatures of fluorescent reporters placed on RNAP and DNA in the presence of ligands locking the clamp in distinct conformations. We report evidence for an unexpected and obligatory step early in the initiation involving a transient clamp closure as a prerequisite for DNA melting. We also present a 2.6-angstrom crystal structure of a late-initiation intermediate harboring a rotationally unconstrained downstream DNA duplex within the open RNAP active site cleft. Our findings explain how RNAP thermal motions control the promoter search and drive DNA melting in the absence of external energy sources. RNA polymerase motions during promoter melting.,Feklistov A, Bae B, Hauver J, Lass-Napiorkowska A, Kalesse M, Glaus F, Altmann KH, Heyduk T, Landick R, Darst SA Science. 2017 May 26;356(6340):863-866. doi: 10.1126/science.aam7858. PMID:28546214 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also RNA polymerase 3D structures Sigma factor 3D structures

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