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Does the DNA Binding Mode of a Molecule Affect its Ability to Interact With Singlet Oxygen?
Author(s) -
Lau Vivian,
Heyne Belinda
Publication year - 2009
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.1751-1097.2009.00559.x
Subject(s) - singlet oxygen , affect (linguistics) , dna , molecule , chemistry , biophysics , mode (computer interface) , oxygen , biology , biochemistry , psychology , communication , computer science , human–computer interaction , organic chemistry
Singlet oxygen is known to be a potent mutagenic agent and several biologically relevant molecules have been proposed to act as scavengers for this noxious species. However, numerous studies have been conducted in homogenous solution and the reactivity of singlet oxygen scavengers known to bind DNA has never been investigated in double‐stranded DNA. In the following paper, we present the results obtained regarding the interaction between 4′,6‐diamidino‐2‐phenylindole (DAPI) and singlet oxygen. We show the molecule to be a potent scavenger of singlet oxygen in aqueous solution with an absolute rate constant (chemical and physical quenching of singlet oxygen) of (1.7 ± 0.3) × 10 7 m −1 s −1 . In addition, we demonstrate that the binding mode of a singlet oxygen scavenger to DNA can strongly influence its reactivity toward singlet oxygen. In the case of DAPI, while the molecule exhibits a chemical reaction with singlet oxygen when the molecule is free in aqueous solution or intercalated in GC sequences of DNA, DAPI becomes chemically unreactive toward singlet oxygen when bound in the minor groove of DNA AT sequences.