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Ru(phen)_2dppz^(2+) Luminescence: Dependence on DNA Sequences and Groove-Binding Agents

Holmlin, R. Erik and Stemp, Eric D. A. and Barton, Jacqueline K. (1998) Ru(phen)_2dppz^(2+) Luminescence: Dependence on DNA Sequences and Groove-Binding Agents. Inorganic Chemistry, 37 (1). pp. 29-34. ISSN 0020-1669. doi:10.1021/ic970869r.

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Emission of Δ-Ru(phen)_2dppz^(2+) bound to nucleic acid polymers of different sequence has been investigated by time-resolved luminescence spectroscopy and the effect of major and minor groove DNA binding agents on the luminescence profile of the complex evaluated. In the presence of a 1:1 mixture of poly d(AT) and poly d(GC), the excited-state decay of Δ-Ru(phen)_2dppz^(2+) can be described by a linear combination of the decay profiles in the presence of poly d(AT) and poly d(GC) independently. This analysis indicates that ∼85% of the complexes are bound to poly d(AT) and that the metallointercalator preferentially occupies AT sites in mixed-sequence polymers such as calf thymus or T4 DNA. When rac-Ru(phen)_2dppz^(2+) bound to [d(5‘-GAGTGCACTC-3‘)_2] is titrated with the major groove intercalator Δ-α-[Rh[(R,R)-Me_2trien]phi]^(3+), the ruthenium emission yield decreases while the absorbance of the π−π^* transition centered on the dppz ligand increases, until saturation behavior is observed at a 1:1 Rh/duplex ratio. These titrations indicate that Ru(phen)_2dppz^(2+) is displaced from the major groove by the rhodium complex. In contrast, for rac-Ru(phen)_2dppz^(2+) bound to poly d(AT), addition of the minor groove binding agent distamycin produces an increase in ruthenium emission which saturates at ∼1 distamycin/5 bp, consistent with the double helix being able to accommodate major and minor groove binders simultaneously. Distamycin has no effect on the emission of Ru(phen)_2dppz^(2+) emission bound to poly d(GC). These photophysical studies establish a sequence preference in binding to DNA by Ru(phen)_2dppz^(2+) as well as providing support for the original assignment by NMR of ruthenium intercalation from the major groove side of the DNA helix.

Item Type:Article
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URLURL TypeDescription
Stemp, Eric D. A.0000-0003-2098-4214
Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 1998 American Chemical Society. Received July 10, 1997. Publication Date (Web): January 12, 1998. We are grateful to the NIH (Grant GM33309) for financial support of this work, the Parsons Foundation for a predoctoral fellowship (R.E.H.), and the American Cancer Society for a postdoctoral fellowship (E.D.A.S.). We also thank B. P. Hudson for material and the Beckman Institute Laser Resource Center.
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Ralph M. Parsons FoundationUNSPECIFIED
American Cancer SocietyUNSPECIFIED
Caltech Beckman InstituteUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20160411-102728744
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Official Citation:Ru(phen)2dppz2+ Luminescence:  Dependence on DNA Sequences and Groove-Binding Agents R. Erik Holmlin, Eric D. A. Stemp, and Jacqueline K. Barton Inorganic Chemistry 1998 37 (1), 29-34 DOI: 10.1021/ic970869r
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:66046
Deposited By: Ruth Sustaita
Deposited On:11 Apr 2016 17:41
Last Modified:10 Nov 2021 23:52

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