Accession Number:

ADA265580

Title:

The Nonnatural Deoxyribonucleoside D3 Incorporated in an Intramolecular DNA Triplex Binds Sequence Specifically by Intercalation

Descriptive Note:

Technical rept.,

Corporate Author:

CALIFORNIA INST OF TECH PASADENA DEPT OF CHEMISTRY

Report Date:

1993-06-01

Pagination or Media Count:

6.0

Abstract:

The synthetic deoxyribonucleoside 1-2-deoxy-Beta-D-ribofuranosyl-4- 3-benzamidophenylimidazole D3 has been shown to specifically recognize both TdotA and Cdot G base pairs when incorporated into the Hoogsteen paired strand of pyrimidine dot purine dot pyrimidine triplexes. To further investigate the binding of D3, a DNA oligonucleotide containing a single D3 residue and designed to form intramolecular triplexes was synthesized and studied by one- and two-dimensional NMR spectroscopy. The oligonucleotide DAGATAGAACCCCTTCTATCTTATATCTD3TCTT was found to form a stable intramolecular triplex, with a CCCC and a TATA loop connecting the Watson-Crick and Hoogsteen paired strands, respectively. Unlike other third strand bases, however, D3 does not hydrogen bond with a Watson-Crick base pair. Instead, it intercalates between its associated base pair TdotA and the adjacent 3 TdotAdotT triplet. The binding mode of D3 is unique in that it not only binds by intercalation but skips a potential base pair to do so. Thus, non-purine bases can be accommodated in the purine strand of DNA triplexes in an entirely new way

Subject Categories:

  • Biochemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE