Caught in the Loop: Binding of the [Ru(phen)2(dppz)]2+ Light‐Switch Compound to Quadruplex DNA in Solution Informed by Time‐Resolved Infrared Spectroscopy. Issue 71 (26th November 2020)

• Record Type: Journal Article
• Authors: Devereux, Stephen J.; Poynton, Fergus E.; Baptista, Frederico R.; Gunnlaugsson, Thorfinnur; Cardin, Christine J.; Sazanovich, Igor V.; Towrie, Michael; Kelly, John M.; Quinn, Susan J.
• Is Part Of: Chemistry. Volume 26:Issue 71(2020)
• Page Start: 17103
• Page End: 17109
• Publication Date: 2020-11-26
• Subjects: light switch -- quadruplex binding -- ruthenium polypyridyl -- time-resolved spectroscopy; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202002165
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Ultrafast time‐resolved infrared (TRIR) is used to report on the binding site of the [Ru(phen)2 (dppz)] 2+ "light‐switch" complex with both bimolecular (Oxytricha nova telomere) and intramolecular (human telomere) guanine‐quadruplex structures in both K + and Na + containing solutions. TRIR permits the simultaneous monitoring both of the "dark" and "bright" states of the complex and of the quadruplex nucleobase bases, the latter via a Stark effect induced by the excited state of the complex. These data are used to establish the contribution of guanine base stacking and loop interactions to the binding site of this biologically relevant DNA structure in solution. A particularly striking observation is the strong thymine signal observed for the Na + form of the human telomere sequence, which is expected to be in the anti‐parallel conformation. Abstract : The sensitivity of DNA base vibrations to a locally excited state is readily observed by time‐resolved infrared spectroscopy. This allows guanine base stack interactions to be distinguished from thymine loop interactions for the [Ru(phen)2 (dppz)] 2+ "light‐switch" bound to quadruplex structures in solution.