Premium
Molecular Beacon Probes of Photodamage in Thymine and Uracil Oligonucleotides ¶
Author(s) -
Yarasi Soujanya,
McConachie Cheryl,
Loppnow Glen R.
Publication year - 2005
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.1751-1097.2005.tb00209.x
Subject(s) - molecular beacon , oligonucleotide , chemistry , thymine , kinetics , irradiation , uracil , nucleic acid , fluorescence , context (archaeology) , photochemistry , dna , biochemistry , physics , optics , biology , paleontology , quantum mechanics , nuclear physics
Molecular beacons (MB) are becoming more common as sequence‐selective detectors of nucleic acids. Although they can easily detect single‐base mismatches, they have never been used to directly detect DNA or RNA damage. To measure the degree of ultraviolet (UV) light damage in oligonucleotides, we report a novel MB approach for general detection of photoproducts in UV‐irradiated rU 17 and dT 17 oligonucleotides. With monochromatic UV light irradiation at ca 280 nm under anoxic conditions, the oligonucleotide absorption decays with a single‐exponential time constant of 123 ± 1 min for rU 17 and with double‐exponential time constants of 78 ± 0.5 min (99%) and 180 ± 5 min (0.05%) for dT 17 oligonucleotides. Under the same conditions, the MB fluorescence decays more quickly, with single‐exponential time constants of 19 ± 2 and 26 ± 3 min for rU 17 and dT 17 , respectively. Similar kinetics were observed with broadband UV light irradiation of oligonucleotides. The differences in the UV damage kinetics of dT 17 and rU 17 and their detection by absorption and fluorescence techniques will be discussed in the context of differential instabilities introduced in the nucleic acid‐MB duplex by the different photoproducts formed.