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Characterization of dipyridophenazine complexes of ruthenium(II): The light switch effect as a function of nucleic acid sequence and conformation

Jenkins, Yonchu and Friedman, Alan E. and Turro, Nicholas J. and Barton, Jacqueline K. (1992) Characterization of dipyridophenazine complexes of ruthenium(II): The light switch effect as a function of nucleic acid sequence and conformation. Biochemistry, 31 (44). pp. 10809-10816. ISSN 0006-2960. doi:10.1021/bi00159a023. https://resolver.caltech.edu/CaltechAUTHORS:20160406-091731528

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Abstract

Spectroscopic parameters for two novel ruthenium complexes on binding to nucleic acids of varying sequences and conformations have been determined. These complexes, Ru(bpy)_2dppz^(2+) and Ru(phen)_2dppz^(2+) (bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline; dppz = dipyrido[3,2:ɑ-2',3':c]phenazine) serve as "molecular light switches" for DNA, displaying no photoluminescence in aqueous solution but luminescing intensely in the presence of DNA. The luminescent enhancement observed upon binding is attributed to the sensitivity of the excited state to quenching by water; in DNA, the metal complex, upon intercalation into the helix, is protected from the aqueous solvent, thereby preserving the luminescence. Correlations between the extent of protection (depending upon the DNA conformation) and the luminescence parameters are observed. Indeed, the strongest luminescent enhancement is observed for intercalation into DNA conformations which afford the greatest amount of overlap with access from the major groove, such as in triple helices. Differences are observed in the luminescent parameters between the two complexes which also correlate with the level of water protection. In the presence of nucleic acids, both complexes exhibit biexponential decays in emission. Quenching studies are consistent with two intercalative binding modes for the dppz ligand from the major groove: one in which the metal-phenazine axis lies along the DNA dyad axis and another where the metal-phenazine axis lies almost perpendicular to the DNA dyad axis. Ru(bpy)_2dppz^(2+) and Ru(phen)_2dppz^(2+) are shown here to be unique reporters of nucleic acid structures and may become valuable in the design of new diagnostics for DNA.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/bi00159a023DOIArticle
http://pubs.acs.org/doi/abs/10.1021/bi00159a023PublisherArticle
ORCID:
AuthorORCID
Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 1992 American Chemical Society. Received June 11, 1992; Revised Manuscript Received August 24, 1992. Publication Date: November 1992. We are grateful to the NIH (GM33309 and an NIH traineeship to Y.J.) for their support of this research.
Funders:
Funding AgencyGrant Number
NIHGM33309
NIH traineeshipUNSPECIFIED
Issue or Number:44
DOI:10.1021/bi00159a023
Record Number:CaltechAUTHORS:20160406-091731528
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20160406-091731528
Official Citation:Characterization of dipyridophenazine complexes of ruthenium(II): The light switch effect as a function of nucleic acid sequence and conformation Yonchu Jenkins, Alan E. Friedman, Nicholas J. Turro, and Jacqueline K. Barton Biochemistry 1992 31 (44), 10809-10816 DOI: 10.1021/bi00159a023
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65957
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:06 Apr 2016 18:02
Last Modified:10 Nov 2021 23:51

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