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Long-range and short-range oxidative damage to DNA: photoinduced damage to guanines in ethidium-DNA assemblies.
Biochemistry 1998; 37(45):15933-40B

Abstract

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 A Et-GG separation) and distal (44 A 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.

Authors+Show Affiliations

Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9843399

Citation

Hall, D B., et al. "Long-range and Short-range Oxidative Damage to DNA: Photoinduced Damage to Guanines in ethidium-DNA Assemblies." Biochemistry, vol. 37, no. 45, 1998, pp. 15933-40.
Hall DB, Kelley SO, Barton JK. Long-range and short-range oxidative damage to DNA: photoinduced damage to guanines in ethidium-DNA assemblies. Biochemistry. 1998;37(45):15933-40.
Hall, D. B., Kelley, S. O., & Barton, J. K. (1998). Long-range and short-range oxidative damage to DNA: photoinduced damage to guanines in ethidium-DNA assemblies. Biochemistry, 37(45), pp. 15933-40.
Hall DB, Kelley SO, Barton JK. Long-range and Short-range Oxidative Damage to DNA: Photoinduced Damage to Guanines in ethidium-DNA Assemblies. Biochemistry. 1998 Nov 10;37(45):15933-40. PubMed PMID: 9843399.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Long-range and short-range oxidative damage to DNA: photoinduced damage to guanines in ethidium-DNA assemblies. AU - Hall,D B, AU - Kelley,S O, AU - Barton,J K, PY - 1998/12/8/pubmed PY - 1998/12/8/medline PY - 1998/12/8/entrez SP - 15933 EP - 40 JF - Biochemistry JO - Biochemistry VL - 37 IS - 45 N2 - 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 A Et-GG separation) and distal (44 A 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. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/9843399/Long_range_and_short_range_oxidative_damage_to_DNA:_photoinduced_damage_to_guanines_in_ethidium_DNA_assemblies_ L2 - https://dx.doi.org/10.1021/bi981750c DB - PRIME DP - Unbound Medicine ER -