1nc0

U80G U6 Intramolecular Stem-Loop RNA from Saccharomyces cerevisiae

spinqualitylabelsall models 1nc0, 18 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1nc0 is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed U6 RNA is essential for nuclear pre-mRNA splicing and has been implicated directly in catalysis of intron removal. The U80G mutation at the essential magnesium binding site of the U6 3' intramolecular stem-loop region (ISL) is lethal in yeast. To further understand the structure and function of the U6 ISL, we have investigated the structural basis for the lethal U80G mutation by NMR and optical spectroscopy. The NMR structure reveals that the U80G mutation causes a structural rearrangement within the ISL resulting in the formation of a new Watson-Crick base pair (C67 x G80), and disrupts a protonated C67 x A79 wobble pair that forms in the wild-type structure. Despite the structural change, the accessibility of the metal binding site is unperturbed, and cadmium titration produces similar phosphorus chemical shift changes for both the U80G mutant and wild-type RNAs. The thermodynamic stability of the U80G mutant is significantly increased (Delta Delta G(fold) = -3.6 +/- 1.9 kcal/mol), consistent with formation of the Watson-Crick pair. Our structural and thermodynamic data, in combination with previous genetic data, suggest that the lethal basis for the U80G mutation is stem-loop hyperstabilization. This hyperstabilization may prevent the U6 ISL melting and rearrangement necessary for association with U4. Structural basis for a lethal mutation in U6 RNA.,Sashital DG, Allmann AM, Van Doren SR, Butcher SE Biochemistry. 2003 Feb 18;42(6):1470-7. PMID:12578359 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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