SOLUTION STRUCTURE AND HYDRATION PATTERNS OF A PYRIMIDINE-CENTER-DOT-PURINE-CENTER-DOT-PYRIMIDINE DNA TRIPLER CONTAINING A NOVEL T-CENTER-DOT-CG BASE-TRIPLE

[摘要] The solution structure of a pyrimidine.purine.pyrimidine DNA tripler 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 tripler code, is stabilized by a single hydrogen bond between the O-2 atom of thy mine 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 str and of the molecule are observed around the cytosine residue in the T.CG triple. Globally, the tripler resembles the solution structure of a previously solved pyrimidine pyrimidine.purine.pyrimidine DNA tripler containing an unusual G.TA triple. Also conserved are the sites and patterns of hydration in the two triplexes.

[发布日期] 1994-08-26

[关键词] DNA;PYRIMIDINE-CENTER-DOT-PURINE-CENTER-DOT-PYRIMIDINE TRIPLEXES;T-CENTER-DOT-CG TRIPLE;NMR SPECTROSCOPY;MOLECULAR DYNAMICS