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Updated: Jan 26, 2026

Author Spotlight: Characterizing DNA G-Quadruplex by Bis-3-Chloropiperidine Based Chemical Mapping
Published on: May 12, 2023
Structural Studies Reveal Enantiospecific Recognition of a DNA G-Quadruplex by a Ruthenium Polypyridyl Complex
Kane McQuaid1,2, Holly Abell1, Sarah P Gurung1,2
1Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK.
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.
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