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Double‐strand break of giant DNA: protection by glucosyl‐hesperidin as evidenced through direct observation on individual DNA molecules
Author(s) -
Yoshikawa Yuko,
Suzuki Mari,
Yamada Norihiro,
Yoshikawa Kenichi
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.04.008
Subject(s) - breakage , hesperidin , dna , chemistry , molecule , cyanine , photochemistry , biophysics , double bond , double strand , dna damage , fluorescence , biochemistry , materials science , biology , polymer chemistry , organic chemistry , optics , medicine , alternative medicine , physics , pathology , composite material
We have performed a real‐time observation of photo‐induced breakage on individual long DNA molecules stained by a cyanine dye, YOYO, under the intense illumination ( λ =450–490 nm) in solution. It was shown that the double‐strand breakage is accelerated by Fenton's reagent (Fe 2+ /H 2 O 2 ). In addition, it was found that the breakage reaction is protected in the presence of a water‐soluble flavonoid, glucosyl‐hesperidin. To interpret the kinetic process of the double‐strand breakage reaction, a two‐step mechanism is proposed: under light illumination on giant DNA molecules, single‐strand breaks are generated to induce nicks in a stochastic manner, and then reactive oxygen attacks these nicks causing the double‐strand break.