1b3p
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(New page: 200px<br /><applet load="1b3p" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b3p" /> '''5'-D(*GP*GP*AP*GP*GP*AP*T)-3''''<br /> ==Ov...)
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Revision as of 21:33, 24 November 2007
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5'-D(*GP*GP*AP*GP*GP*AP*T)-3'
Overview
BACKGROUND: Triplet repeat sequences are of considerable biological, importance as the expansion of such tandem arrays can lead to the onset of, a range of human diseases. Such sequences can self-pair via mismatch, alignments to form higher order structures that have the potential to, cause replication blocks, followed by strand slippage and sequence, expansion. The all-purine d(GGA)n triplet repeat sequence is of particular, interest because purines can align via G.G, A.A and G.A mismatch, formation. RESULTS: We have solved the structure of the uniformly, 13C,15N-labeled d(G1-G2-A3-G4-G5-A6-T7) sequence in 10 mM Na+ solution., This sequence adopts a novel twofold-symmetric duplex fold where, interlocked V-shaped arrowhead motifs are aligned solely via interstrand, G1.G4, G2.G5 and A3.A6 mismatch formation. The tip of the arrowhead motif, is centered about the p-A3-p step, and symmetry-related local, parallel-stranded duplex domains are formed by the G1-G2-A3 and G4-G5-A6, segments of partner strands. CONCLUSIONS: The purine-rich (GGA)n triplet, repeat sequence is dispersed throughout the eukaryotic genome. Several, features of the arrowhead duplex motif for the (GGA)2 triplet repeat, provide a unique scaffold for molecular recognition. These include the, large localized bend in the sugar-phosphate backbones, the segmental, parallel-stranded alignment of strands and the exposure of the, Watson-Crick edges of several mismatched bases.
About this Structure
1B3P is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Interlocked mismatch-aligned arrowhead DNA motifs., Kettani A, Bouaziz S, Skripkin E, Majumdar A, Wang W, Jones RA, Patel DJ, Structure. 1999 Jul 15;7(7):803-15. PMID:10425682
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