Solution Structure of a Hexitol Nucleic Acid Duplex with Four Consecutive T⋅T Base Pairs

✍ Scribed by Eveline Lescrinier; Robert M. Esnouf; Jan Schraml; Roger Busson; Piet Herdewijn

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: German
• Weight: 717 KB
• Volume: 83
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/1522-2675(20000705)83:7<1291::aid-hlca1291>3.0.co;2-t

✦ Synopsis

The structure of the hexitol nucleic acid (HNA) h(GCGCTTTTGCGC) was determined by NMR spectroscopy. This unnatural nucleic acid was developed as a mimic for A-RNA. In solution, the studied sequence is forming a symmetric double-stranded structure with four central consecutive T ´T wobble pairs flanked by G ´C Watson-Crick base pairs. The stem regions adopt an A-type helical structure. Discrete changes in backbone angles are altering the course of the helix axis in the internal loop region. Two H-bonds are formed in each wobble pair, and base stacking is preserved in the duplex, explaining the stability of the duplex. This structure elucidation provides information about the influence of a (T) 4 fragment on local helix geometries as well as on the nature of the T ´T mismatch base pairing in a TTTT tract.