Abstract
The solution structure of a pyrimidine purine pyrimidine DNA triplex containing a novel T·CG base-triple has been determined via two and three-dimensional NMR spectroscopy and restrained molecular dynamics simulations incorporating explicit solvent and counter-ions. The T·CG triple, which expands the triplex code, is stabilized by a single hydrogen bond between the O-2 atom of thymine and the free amino proton of cytosine in the Watson-Crick C·G base-pair. This hydrogen bonding alignment produces large variations in helical twist at the dinucleotide steps involving the thymine residue. Localized structural perturbations in the purine-rich strand of the molecule are observed around the cytosine residue in the T·CG triple. Globally, the triplex resembles the solution structure of a previously solved pyrimidine-purine-pyrimidine DNA triplex containing an unusual G·TA triple. Also conserved are the sites and patterns of hydration in the two triplexes.
Original language | English (US) |
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Pages (from-to) | 600-619 |
Number of pages | 20 |
Journal | Journal of Molecular Biology |
Volume | 241 |
Issue number | 4 |
DOIs | |
State | Published - 1994 |
Keywords
- DNA
- Molecular dynamics
- NMR spectroscopy
- Pyrimidine·purine·pyrimidine triplexes
- T·CG triple
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology