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Recognition of DNA Base Pair Mismatches by a Cyclometalated Rh(III) Intercalator

Kisko, Jennifer L. and Barton, Jacqueline K. (2000) Recognition of DNA Base Pair Mismatches by a Cyclometalated Rh(III) Intercalator. Inorganic Chemistry, 39 (21). pp. 4942-4949. ISSN 0020-1669. doi:10.1021/ic000549z.

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Two cyclometalated complexes of Rh(III), rac-[Rh(ppy)_2chrysi]^+ and rac-[Rh(ppy)_2phi]^+, have been synthesized and characterized with respect to their binding to DNA. The structure of rac-[Rh(ppy)_2phi]Cl·H_2O·CH_2Cl_2 has been determined by X-ray diffraction (monoclinic, P2_1/c, Z = 4, a =18.447(3) Å, b = 9.770(1) Å, c = 17.661(3) Å, β = 94.821(11)°, V = 3172.0(8) Å^3) and reveals that the complex is a distorted octahedron with nearly planar ligands, similar in structure to the DNA mismatch recognition agent [Rh(bpy)_2chrysi]^(3+). The 2-phenylpyridyl nitrogen atoms are shown to be in the axial positions, as a result of trans-directing effects. This tendency simplifies the synthesis and purification of such complexes by limiting the number of possible isomers generated. The abilities of [Rh(ppy)_2chrysi]^+ and [Rh(ppy)_2phi]^+ to bind and, with photoactivation, to cleave DNA have been demonstrated in assays on duplex DNA in the absence and presence of a single CC mismatch. [Rh(ppy)_2chrysi]^+ was shown upon photoactivation to cleave DNA selectively at the base pair mismatch whereas [Rh(ppy)_2phi]^+ cleaves B-DNA nonspecifically. The reactivity of [Rh(ppy)_2chrysi]^+ was also compared to that of the known mismatch recognition agent [Rh(bpy)_2chrysi]^(3+). Competitive photocleavage studies revealed that a 14-fold excess of [Rh(ppy)_2chrysi]^+ was required to achieve the same level of binding as that of [Rh(bpy)_2chrysi]^(3+). However, the ratio of damage induced by [Rh(bpy)_2chrysi]^(3+) to that induced by [Rh(ppy)_2chrysi]^+ is considerably greater than this value, indicating that decreased photoefficiency for the cyclometalated complex must contribute to its significantly attenuated photoreactivity. These cyclometalated intercalators provide the starting points for the design of a new family of metal complexes targeted to DNA.

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Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 2000 American Chemical Society. Received May 23, 2000. Publication Date (Web): September 21, 2000. We gratefully acknowledge the National Institutes of Health (GM33309) for financial support of this work and for a postdoctoral fellowship to J.L.K. We are also grateful to Lawrence M. Henling at the Caltech X-ray Crystallography Laboratory for his technical expertise, and we thank D. T. Odom, H. Junicke, and M. Pascaly for helpful discussions.
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NIH Postdoctoral FellowshipUNSPECIFIED
Issue or Number:21
Record Number:CaltechAUTHORS:20160209-152113459
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Official Citation:Recognition of DNA Base Pair Mismatches by a Cyclometalated Rh(III) Intercalator Jennifer L. Kisko and Jacqueline K. Barton Inorganic Chemistry 2000 39 (21), 4942-4949 DOI: 10.1021/ic000549z
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64347
Deposited By: George Porter
Deposited On:09 Feb 2016 23:36
Last Modified:10 Nov 2021 23:29

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