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Luminescence of ruthenium(II) polypyridyls: evidence for intercalative binding to Z-DNA

Friedman, Alan E. and Kumar, Challa V. and Turro, Nicholas J. and Barton, Jacqueline K. (1991) Luminescence of ruthenium(II) polypyridyls: evidence for intercalative binding to Z-DNA. Nucleic Acids Research, 19 (10). pp. 2595-2602. ISSN 0305-1048.

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Photophysical studies have been undertaken to characterize the binding interactions of enantiomers of Ru(phen)_3^(2+), Ru(DIP)_3^(2+), and racemic Ru(bpy)_2dppz^(2+) (where phen = 1,10-phenanthroline, DIP = 4,7-diphenylphenanthroline, and dppz = dipyridophenazine) with Z-form poly d(GC). Parallel enhancements in steady state luminescent intensity and a lengthening of luminescent lifetimes are seen for ruthenium enantiomers with Z-DNA as for B-DNA but with enantioselectivities reversed. Greater enhancements are seen for delta-isomers with the right-handed helix but for lambda-isomers with the left-handed helix. Ru(bpy)_2dppz^(2+), an avid intercalator in B-DNA, displays no luminescence free in aqueous solution, but luminesces brightly bound to either B- or Z-poly d(GC). Stern-Volmer quenching studies also support the enantioselective preference in binding to B-DNA by Δ-isomers and a reversal with binding to Z-DNA preferentially by the Λ-isomers. Steady state polarization studies indicate a rigid association of the complexes with both B- and Z-DNA on the time-scale of their emission and again with symmetrical enantioselectivities for the left and right-handed helices. Given the well characterized intercalative association of the complexes with B-DNA, the parallel results seen here with Z-DNA point strongly to a comparable intercalative association with the Z-form helix. That molecules may interact with Z-DNA through intercalation has not been demonstrated previously and now requires consideration in describing the range of interactions of small molecules and proteins with Z-DNA.

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Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 1991 Oxford University Press. Received March 6, 1991; Revised and Accepted April 26, 1991. We are grateful to the National Institutes of Health (GM33309 to J.K.B. and an NRSA to A.E.F.) and to the National Science Foundation and the Air Force Office of Scientific Research (to N.J.T.) for their financial support. In addition, we thank Dr. Jay Winkler for his spectroscopic expertise.
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NIH Predoctoral FellowshipUNSPECIFIED
Air Force Office of Scientific Research (AFOSR)UNSPECIFIED
Issue or Number:10
Record Number:CaltechAUTHORS:20160406-134002391
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Official Citation:Luminescence of ruthenium(II) polypyridyls: evidence for intercalative binding to Z-DNA. A E Friedman, C V Kumar, N J Turro, and J K Barton Nucleic Acids Res. 1991 May 25; 19(10): 2595–2602
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65969
Deposited By: Ruth Sustaita
Deposited On:06 Apr 2016 21:45
Last Modified:03 Oct 2019 09:52

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