5ohq

Crystal structure of the KOW6-KOW7 domain of human DSIF

spinqualitylabelsall models 5ohq, resolution 1.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5ohq is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.098Å Ligands: CL, NA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SPT5H_HUMAN Component of the DRB sensitivity-inducing factor complex (DSIF complex), which regulates mRNA processing and transcription elongation by RNA polymerase II. DSIF positively regulates mRNA capping by stimulating the mRNA guanylyltransferase activity of RNGTT/CAP1A. DSIF also acts cooperatively with the negative elongation factor complex (NELF complex) to enhance transcriptional pausing at sites proximal to the promoter. Transcriptional pausing may facilitate the assembly of an elongation competent RNA polymerase II complex. DSIF and NELF promote pausing by inhibition of the transcription elongation factor TFIIS/S-II. TFIIS/S-II binds to RNA polymerase II at transcription pause sites and stimulates the weak intrinsic nuclease activity of the enzyme. Cleavage of blocked transcripts by RNA polymerase II promotes the resumption of transcription from the new 3' terminus and may allow repeated attempts at transcription through natural pause sites. DSIF can also positively regulate transcriptional elongation and is required for the efficient activation of transcriptional elongation by the HIV-1 nuclear transcriptional activator, Tat. DSIF acts to suppress transcriptional pausing in transcripts derived from the HIV-1 LTR and blocks premature release of HIV-1 transcripts at terminator sequences. Publication Abstract from PubMed During transcription, RNA polymerase II (Pol II) associates with the conserved elongation factor DSIF. DSIF renders the elongation complex stable and functions during Pol II pausing and RNA processing. We combined cryo-EM and X-ray crystallography to determine the structure of the mammalian Pol II-DSIF elongation complex at a nominal resolution of 3.4 A. Human DSIF has a modular structure with two domains forming a DNA clamp, two domains forming an RNA clamp, and one domain buttressing the RNA clamp. The clamps maintain the transcription bubble, position upstream DNA, and retain the RNA transcript in the exit tunnel. The mobile C-terminal region of DSIF is located near exiting RNA, where it can recruit factors for RNA processing. The structure provides insight into the roles of DSIF during mRNA synthesis. Structure of a transcribing RNA polymerase II-DSIF complex reveals a multidentate DNA-RNA clamp.,Bernecky C, Plitzko JM, Cramer P Nat Struct Mol Biol. 2017 Sep 11. doi: 10.1038/nsmb.3465. PMID:28892040 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Elongation factor 3D structures

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