Structural Studies Reveal Enantiospecific Recognition of a DNA G-Quadruplex by a Ruthenium Polypyridyl Complex.
McQuaid, K., Abell, H., Gurung, S.P., Allan, D.R., Winter, G., Sorensen, T., Cardin, D.J., Brazier, J.A., Cardin, C.J., Hall, J.P.(2019) Angew Chem Int Ed Engl 58: 9881-9885
- PubMed: 30958918 
- DOI: https://doi.org/10.1002/anie.201814502
- Primary Citation of Related Structures:  
5LS8 - PubMed Abstract: 
By using X-ray crystallography, we show that the complexes Λ/Δ-[Ru(TAP) 2 (11-CN-dppz)] 2+ (TAP=1,4,5,8-tetraazaphenanthrene, dppz=dipyridophenazine) bind DNA G-quadruplex in an enantiospecific manner that parallels the specificity of these complexes with duplex DNA. The Λ complex crystallises with the normally parallel stranded d(TAGGGTTA) tetraplex to give the first such antiparallel strand assembly in which syn-guanosine is adjacent to the complex at the 5' end of the quadruplex core. SRCD measurements confirm that the same conformational switch occurs in solution. The Δ enantiomer, by contrast, is present in the structure but stacked at the ends of the assembly. In addition, we report the structure of Λ-[Ru(phen) 2 (11-CN-dppz)] 2+ bound to d(TCGGCGCCGA), a duplex-forming sequence, and use both structural models to provide insight into the motif-specific luminescence response of the isostructural phen analogue enantiomers.
Organizational Affiliation: 
Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK.