177d

Publication Abstract from PubMed

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.

Solution structure and hydration patterns of a pyrimidine.purine.pyrimidine DNA triplex containing a novel T.CG base-triple.,Radhakrishnan I, Patel DJ J Mol Biol. 1994 Aug 26;241(4):600-19. PMID:8057381^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.