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Anthraquinone Photonucleases: A Surprising Role for Chloride in the Sequence‐Neutral Cleavage of DNA and the Footprinting of Minor Groove‐Bound Ligands
Author(s) -
Armitage Bruce,
Schuster Gary B.
Publication year - 1997
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1997.tb08638.x
Subject(s) - chemistry , cleavage (geology) , deoxyribose , dna , netropsin , chloride , footprinting , stereochemistry , photochemistry , minor groove , crystallography , biochemistry , organic chemistry , geotechnical engineering , fracture (geology) , engineering , base sequence
Irradiation of water‐soluble anthraquinone (AQ) reagents in the presence of chloride ions results in the spontaneous, sequence‐neutral cleavage of DNA. Mechanistic studies indicate that cleavage is initiated by chlorine atoms, produced by charge transfer interaction between chloride anion and AQ triplet states. High‐resolution gel electrophoresis suggests that cleavage arises from abstraction of a hydrogen atom from C‐4′ of deoxyribose units. The targeting of this hydrogen, which is located in the minor groove of duplex DNA, can be effectively blocked by netropsin and, to a lesser degree, berenil, leading to photofootprinting of these minor groove‐binding drugs.