1nc0
From Proteopedia
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U80G U6 Intramolecular Stem-Loop RNA from Saccharomyces cerevisiae
Overview
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.
About this Structure
1NC0 is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Sat Nov 24 22:54:58 2007
