Download MendeleyX-ray Crystal Structures Show DNA Stacking Advantage of Terminal Nitrile Substitution in Ru-dppz Complexes.
McQuaid, K., Hall, J.P., Brazier, J.A., Cardin, D.J., Cardin, C.J.(2018) Chemistry 24: 15859-15867
- PubMed: 30063271
- DOI: https://doi.org/10.1002/chem.201803021
- Primary Citation of Related Structures:
5NBE, 6G8S, 6GLD, 6R6D - PubMed Abstract:
The new complexes [Ru(TAP) 2 (11-CN-dppz)] 2+ , [Ru(TAP) 2 (11-Br-dppz)] 2+ and [Ru(TAP) 2 (11,12-diCN-dppz)] 2+ are reported. The addition of nitrile substituents to the dppz ligand of the DNA photo-oxidising complex [Ru(TAP) 2 (dppz)] 2+ promote π-stacking interactions and ordered binding to DNA, as shown by X-ray crystallography. The structure of Λ-[Ru(TAP) 2 (11-CN-dppz)] 2+ with the DNA duplex d(TCGGCGCCGA) 2 shows, for the first time with this class of complex, a closed intercalation cavity with an AT base pair at the terminus. The structure obtained is compared to that formed with the 11-Br and 11,12-dinitrile derivatives, highlighting the stabilization of syn guanine by this enantiomer when the terminal base pair is GC. In contrast the AT base pair has the normal Watson-Crick orientation, highlighting the difference in charge distribution between the two purine bases and the complementarity of the dppz-purine interaction. The asymmetry of the cavity highlights the importance of the purine-dppz-purine stacking interaction.
Organizational Affiliation:
Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK.
