1guc
From Proteopedia
SOLUTION NMR STRUCTURE OF AN RNA WITH TANDEM, SYMMETRIC GU MISMATCHES, 30 STRUCTURES
Overview
The duplex (rGAGGUCUC)2 contains the motif [sequence: see text] which is unusually stable compared with other symmetric tandem GU mismatches and occurs in the P5 helix of the group I intron of Tetrahymena thermophila. The three-dimensional solution structure of (rGAGGUCUC)2 was determined using two-dimensional NMR and a simulated annealing protocol. The structure is remarkably similar to the A-DNA crystal structure of (dGGGGTCCC)2 [Kneale, G., Brown, T., & Kennard, O. (1985) J. Mol. Biol. 186, 805-814] which contains the analogous motif [sequence: see text]. Incorporation of the [sequence: see text] motif has little effect on backbone torsion angles and helical parameters compared with standard A-form. The only significant departure from A-form is a slight overtwisting 5' of the G in the GU mismatch and a displacement of the mismatches toward the minor groove. Inspection of stacking patterns of this structure and comparison with symmetric tandem GT mismatches in A-DNA oligonucleotides from crystal structure data suggest that electrostatics are important in determining motif stability.
About this Structure
Full crystallographic information is available from OCA.
Reference
Investigation of the structural basis for thermodynamic stabilities of tandem GU mismatches: solution structure of (rGAGGUCUC)2 by two-dimensional NMR and simulated annealing., McDowell JA, Turner DH, Biochemistry. 1996 Nov 12;35(45):14077-89. PMID:8916893 Page seeded by OCA on Fri May 2 18:01:03 2008
