315d
From Proteopedia
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CRYSTAL STRUCTURE OF AN ALTERNATING OCTAMER R(GUAUGUA)D(C) WITH ADJACENT G-U WOBBLE PAIRS
Overview
The crystal structure of the RNA duplex, r(GUAUGUA)dC, with a 3'-terminal, deoxy C residue, has been determined at 1.38 A resolution. The r(GUAUGU), hexameric consensus sequence is present at the exon-intron junction in, pre-mRNAs of yeast and higher eukaryotic organisms. The crystal belongs to, the rhombohedral space group R3. The hexagonal unit cell dimensions are a, = b = 39.71 A, c = 68.15 A and gamma = 120 degrees with one duplex in the, asymmetric unit. The structure was solved using the molecular replacement, method. The final model contains 332 atoms of the duplex and 67 solvent, molecules. The R-factor is 17.6% (Rfree of 23.1%) for 4035 reflections, with F > or = 1.5sigma(F) in the resolution range 10.0 to 1.38 A. The, duplex is of the A-type with a pseudodyad relating the two strands. The, RNA helix is slightly distorted, in spite of the presence of two adjacent, G x U wobble base-pairs located at the center of the helix. The twist, angle between the wobble pairs, 38.1 degrees, is above the average value, and those between the wobble base-pairs and the flanking Watson-Crick, base-pairs, 26.7 degrees and 26.3 degrees, respectively, are lower than, the average values. The twist between the junction base-pairs are about 24, degrees. The G x U wobble pairs are bridged by water molecules and, solvated in the grooves. G x U base-pairs are as stable as the, Watson-Crick A x U pairs and only slightly less stable than the G x C, pairs accounting for their frequent occurrence in RNA.
About this Structure
315D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Crystal structure of an alternating octamer r(GUAUGUA)dC with adjacent G x U wobble pairs., Biswas R, Wahl MC, Ban C, Sundaralingam M, J Mol Biol. 1997 Apr 18;267(5):1149-56. PMID:9150403
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