Controlled Dehydration of a Ruthenium Complex–DNA Crystal Induces Reversible DNA Kinking

Autor: Cora Alberti, J. Sanchez-Weatherby, Kyra O’Sullivan, John A. Brazier, Christine J. Cardin, Graeme Winter, David J. Cardin, Caroline Hurtado Quimper, John M. Kelly, James P. Hall, Thomas Sorensen
Rok vydání: 2014
Předmět:
Zdroj: Journal of the American Chemical Society. 136:17505-17512
ISSN: 1520-5126
0002-7863
DOI: 10.1021/ja508745x
Popis: Hydration-dependent DNA deformation has been known since Rosalind Franklin recognized that the relative humidity of the sample had to be maintained to observe a single conformation in DNA fiber diffraction. We now report for the first time the crystal structure, at the atomic level, of a dehydrated form of a DNA duplex and demonstrate the reversible interconversion to the hydrated form at room temperature. This system, containing d(TCGGCGCCGA) in the presence of Λ-[Ru(TAP)2(dppz)](2+) (TAP = 1,4,5,8-tetraazaphenanthrene, dppz = dipyrido[3,2-a:2',3'-c]phenazine), undergoes a partial transition from an A/B hybrid to the A-DNA conformation, at 84-79% relative humidity. This is accompanied by an increase in kink at the central step from 22° to 51°, with a large movement of the terminal bases forming the intercalation site. This transition is reversible on rehydration. Seven data sets, collected from one crystal at room temperature, show the consequences of dehydration at near-atomic resolution. This result highlights that crystals, traditionally thought of as static systems, are still dynamic and therefore can be the subject of further experimentation.
Databáze: OpenAIRE