title: Effect of various intercalators on the fenton-type oxidative cleavage of double-stranded DNA.
abstract: The intensity of the linear dichroism (LD) in the absorption region of DNA (about 260 nm) decreased with time in the presence of [Fe(EDTA)](2+) (EDTA = ethylenediaminetetraacetic acid), H2O2, and ascorbate. The decrease in the LD signal indicated either an increase in flexibility, a shortening of the DNA stem, or both, owing to oxidative cleavage, and was best described by the difference between the two single-exponential-decay curves, thereby suggesting the involvement of two sequential first-order reactions. The fast reaction was assigned to cleavage of one of two DNA strands, which increased the flexibility of the DNA. The slow reaction corresponded to cleavage at or near the first cleavage site, thereby shortening the DNA stem. The presence of an intercalator, including ethidium, propidium, 9-aminoacridine, and proflavine, inhibited the first step of the cleavage reaction. One of the possible reasons for the observed inhibition might be a change in the DNA conformation near the intercalation site. Intercalation caused an unwinding and elongation of the DNA and resulted in changes in the location of the H atoms of the sugar moiety, which is known to be the main site at which hydroxyl radicals react.
authors.affiliation: Department of Chemistry, Yeungnam University, Dae-dong, Gyeongsan City, Gyeong-buk, 712-749 (Republic of Korea), Fax: (+82) 53-815-5412.
authors.forename: Hyeon Jeong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Giwoong
authors.initials: G
authors.lastname: Sung
authors.forename: Gyeongwon
authors.initials: G
authors.lastname: Kim
authors.forename: Jongjin
authors.initials: J
authors.lastname: Park
authors.forename: Biao
authors.initials: B
authors.lastname: Jin
authors.forename: Seog K
authors.initials: SK
authors.lastname: Kim
mesh_terms: D001205:Ascorbic Acid; D004247:DNA / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide; D007364:Intercalating Agents / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D005290:Ferric Compounds; D007364:Intercalating Agents; D004247:DNA; D004492:Edetic Acid; D006861:Hydrogen Peroxide; C019179:Fe(III)-EDTA; D001205:Ascorbic Acid
keywords: DNA structures; Fenton reaction; cleavage reactions; intercalations; linear dichroism