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Long-Range and Short-Range Oxidative Damage to DNA: Photoinduced Damage to Guanines in Ethidium−DNA Assemblies

Hall, Daniel B. and Kelley, Shana O. and Barton, Jacqueline K. (1998) Long-Range and Short-Range Oxidative Damage to DNA: Photoinduced Damage to Guanines in Ethidium−DNA Assemblies. Biochemistry, 37 (45). pp. 15933-15940. ISSN 0006-2960. doi:10.1021/bi981750c.

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Short-range and long-range photoreactions between ethidium and DNA have been characterized. While no DNA reaction is observed upon excitation into the visible absorption band of ethidium, higher-energy irradiation (313−340 nm) leads both to direct strand cleavage at the 5‘-G of 5‘-GG-3‘ doublets and to piperidine-sensitive lesions at guanine. This reactivity is not consistent with oxidation of guanine by either electron transfer or singlet oxygen as shown by comparison with reactions of a rhodium intercalator and methylene blue, respectively. By covalently tethering ethidium to one end of a DNA duplex, we demonstrate the presence of two distinct reactions, one short-range and the other long-range. The short-range reaction involves a covalent modification of guanine by ethidium, based upon HPLC analysis of the nucleoside products and studies with ethidium derivatives. The long-range reaction is entirely consistent with oxidation of guanine by DNA-mediated electron transfer. The yield of this electron-transfer reaction is not attenuated with distance; equal yields of guanine damage are observed at a proximal (17 Å Et−GG separation) and distal (44 Å Et−GG separation) site. These results are quite similar to those previously observed with a covalently tethered rhodium photooxidant and underscore the unique ability of the DNA base stack to facilitate long-range electron transfer so as to effect oxidative damage from a distance.

Item Type:Article
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URLURL TypeDescription
Kelley, Shana O.0000-0003-3360-5359
Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 1998 American Chemical Society. Received July 21, 1998; Revised Manuscript Received September 11, 1998. Publication Date (Web): October 16, 1998. This work was supported by a grant from the NIH (GM49216). In addition, we thank the NIH for NRSA trainee fellowships given to D.B.H. and S.O.K.
Funding AgencyGrant Number
NIH Predoctoral FellowshipUNSPECIFIED
Issue or Number:45
Record Number:CaltechAUTHORS:20160407-115522973
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Official Citation:Long-Range and Short-Range Oxidative Damage to DNA:  Photoinduced Damage to Guanines in Ethidium−DNA Assemblies Daniel B. Hall, Shana O. Kelley, and Jacqueline K. Barton Biochemistry 1998 37 (45), 15933-15940 DOI: 10.1021/bi981750c
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65988
Deposited By: Ruth Sustaita
Deposited On:08 Apr 2016 15:24
Last Modified:10 Nov 2021 23:51

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