3llm
Crystal Structure Analysis of a RNA HelicaseCrystal Structure Analysis of a RNA Helicase
Structural highlights
FunctionDHX9_HUMAN Unwinds double-stranded DNA and RNA in a 3' to 5' direction. Alteration of secondary structure may subsequently influence interactions with proteins or other nucleic acids. Functions as a transcriptional activator. Component of the CRD-mediated complex that promotes MYC mRNA stability. Involved with LARP6 in the stabilization of type I collagen mRNAs for CO1A1 and CO1A2. As component of a large PER complex is involved in the inhibition of 3' transcriptional termination of circadian target genes such as PER1 and NR1D1 and the control of the circadian rhythms. Positively regulates HIV-1 LTR-directed gene expression.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedRNA helicases of the DExD/H-box superfamily are critically involved in all RNA-related processes. No crystal structures of human DExH-box domains had been determined previously, and their structures were difficult to predict owing to the low level of homology among DExH-motif-containing proteins from diverse species. Here we present the crystal structures of the conserved domain 1 of the DEIH-motif-containing helicase DHX9 and of the DEAD-box helicase DDX20. Both contain a RecA-like core, but DHX9 differs from DEAD-box proteins in the arrangement of secondary structural elements and is more similar to viral helicases such as NS3. The N-terminus of the DHX9 core contains two long alpha-helices that reside on the surface of the core without contributing to nucleotide binding. The RNA-polymerase-II-interacting minimal transactivation domain sequence forms an extended loop structure that resides in a hydrophobic groove on the surface of the DEIH domain. DHX9 lacks base-selective contacts and forms an unspecific but important stacking interaction with the base of the bound nucleotide, and our biochemical analysis confirms that the protein can hydrolyze ATP, guanosine 5'-triphosphate, cytidine 5'-triphosphate, and uridine 5'-triphosphate. Together, these findings allow the localization of functional motifs within the three-dimensional structure of a human DEIH helicase and show how these enzymes can bind nucleotide with high affinity in the absence of a Q-motif. Crystal structure of human RNA helicase A (DHX9): structural basis for unselective nucleotide base binding in a DEAD-box variant protein.,Schutz P, Wahlberg E, Karlberg T, Hammarstrom M, Collins R, Flores A, Schuler H J Mol Biol. 2010 Jul 23;400(4):768-82. Epub 2010 May 25. PMID:20510246[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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