3c4b

Structure of RNaseIIIb and dsRNA binding domains of mouse Dicer

spinqualitylabelsall models 3c4b, resolution 1.68Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3c4b is a 1 chain structure with sequence from Lk3 transgenic mice. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: MSE, OCS Related: 3c4t Gene: Dicer1, Dicer, Mdcr (LK3 transgenic mice) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DICER_MOUSE] Required for formation of the RNA induced silencing complex (RISC). Component of the RISC loading complex (RLC), also known as the micro-RNA (miRNA) loading complex (miRLC), which is composed of DICER1, EIF2C2/AGO2 and TARBP2. Within the RLC/miRLC, DICER1 and TARBP2 are required to process precursor miRNAs (pre-miRNAs) to mature miRNAs and then load them onto EIF2C2/AGO2. EIF2C2/AGO2 bound to the mature miRNA constitutes the minimal RISC and may subsequently dissociate from DICER1 and TARBP2. Also cleaves double-stranded RNA to produce short interfering RNAs (siRNAs) which target the selective destruction of complementary RNAs (By similarity). Involved in cleaving double-stranded RNA in the RNA interference (RNAi) pathway. It produces 21 to 23 bp dsRNAs (siRNAs) which target the selective destruction of homologous RNAs. 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 PubMed Dicer, an RNase III enzyme, initiates RNA interference by processing precursor dsRNAs into mature microRNAs and small-interfering RNAs. It is also involved in loading and activation of the RNA-induced silencing complex. Here, we report the crystal structures of a catalytically active fragment of mouse Dicer, containing the RNase IIIb and dsRNA binding domains, in its apo and Cd(2+)-bound forms, at 1.68- and 2.8-A resolution, respectively. Models of this structure with dsRNA reveal that a lysine residue, highly conserved in Dicer RNase IIIa and IIIb domains and in Drosha RNase IIIb domains, has the potential to participate in the phosphodiester bond cleavage reaction by stabilizing the transition state and leaving group of the scissile bond. Mutational and enzymatic assays confirm the importance of this lysine in dsRNA cleavage, suggesting that this lysine represents a conserved catalytic residue of Dicers. The structures also reveals a approximately 45-aa region within the RNase IIIb domain that harbors an alpha-helix at the N-terminal half and a flexible loop at the C-terminal half, features not present in previously reported structures of homologous RNase III domains from either bacterial RNase III enzymes or Giardia Dicer. N-terminal residues of this alpha-helix have the potential to engage in minor groove interaction with dsRNA substrates. Structural and biochemical insights into the dicing mechanism of mouse Dicer: a conserved lysine is critical for dsRNA cleavage.,Du Z, Lee JK, Tjhen R, Stroud RM, James TL Proc Natl Acad Sci U S A. 2008 Feb 19;105(7):2391-6. Epub 2008 Feb 11. PMID:18268334 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribonuclease 3D structures

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