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Sensitivity of Ru(bpy)_2dppz^(2+) Luminescence to DNA Defects

Lim, Mi Hee and Song, Hang and Olmon, Eric D. and Dervan, Elizabeth E. and Barton, Jacqueline K. (2009) Sensitivity of Ru(bpy)_2dppz^(2+) Luminescence to DNA Defects. Inorganic Chemistry, 48 (12). pp. 5392-5397. ISSN 0020-1669. PMCID PMC2747521. doi:10.1021/ic900407n.

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The luminescent characteristics of Ru(bpy)_2dppz^(2+) (dppz = dipyrido[3,2-a:2′,3′-c]phenazine), a DNA light switch, were investigated in the presence of oligonucleotides containing single base mismatches or an abasic site. In water, the ruthenium luminescence is quenched, but, bound to well matched duplex DNA, the Ru complex luminesces. Here we show that with DNAs containing a defect, rac-, Δ-, and Λ-Ru(bpy)_2dppz^(2+) exhibit significant luminescent enhancements above that with well matched DNA. In the presence of a single base mismatch, large luminescent enhancements are evident for the Δ-Ru isomer; the Λ-isomer shows particularly high luminescence bound to an oligonucleotide containing an abasic site. Similar increases are not evident with two common DNA-binding organic fluorophores, ethidium bromide and TO-PRO-3. Titrations with hairpin oligonucleotides containing a variable mismatch site show correlation between the level of luminescent enhancement and the thermodynamic destabilization associated with the mismatch. This correlation is reminiscent of that found earlier for a bulky rhodium complex that binds mismatched DNA sites through metalloinsertion, where the complex binds the DNA from the minor groove side, ejecting the mismatched bases into the major groove. Differential quenching studies with minor and major groove quenchers and time-resolved emission studies support this metalloinsertion mode for the dppz complex at the defect site. Certainly these data underscore the utility of Ru(bpy)_2dppz^(2+) as a sensitive luminescent reporter of DNA and its defects.

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URLURL TypeDescription CentralArticle
Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:Copyright © 2009 American Chemical Society. Received February 27, 2009. Publication Date (Web): May 19, 2009. We are grateful to the NIH (GM33309) for their financial support and the Tobacco-Related Disease Research Program (TRDRP) for a postdoctoral fellowship to M.H.L. We thank the Beckman Institute Laser Resource Center at Caltech for facilities.
Funding AgencyGrant Number
California Tobacco-Related Disease Research ProgramUNSPECIFIED
Issue or Number:12
PubMed Central ID:PMC2747521
Record Number:CaltechAUTHORS:20090824-113601367
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15269
Deposited By: George Porter
Deposited On:11 Sep 2009 15:57
Last Modified:08 Nov 2021 23:17

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