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Molecular Beacon Probes of Oligonucleotides Photodamaged by Psoralen
Author(s) -
Shire Zahra J.,
Loppnow Glen R.
Publication year - 2012
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.1751-1097.2012.01109.x
Subject(s) - chemistry , adduct , molecular beacon , oligonucleotide , fluorescence , psoralen , mass spectrometry , photochemistry , dna , chromatography , biochemistry , organic chemistry , physics , quantum mechanics
Ultraviolet A (UVA)‐irradiated 4′‐hydroxymethyl‐4,5′,8‐trimethyl psoralen (HMT) in the presence of a poly‐dT 17 and dA 7 TTA 8 oligonucleotides produces HMT–dT 17 and HMT–dA 7 TTA 8 adducts in aqueous solution. In this article, we determine whether these HMT–dT 17 and HMT–dA 7 TTA 8 adducts can be detected with a molecular beacon (MB) probe. We measure the degree of damage in dT 17 and dA 7 TTA 8 solutions containing UVA‐activated HMT via monitoring the decrease in MB fluorescence. Photoproduct formation is confirmed by MALDI‐TOF MS (matrix‐assisted laser desorption/ionization time‐of‐fight mass spectrometry measurements) and absorption spectroscopy. The MB fluorescence decreases upon UVA irradiation in the presence of HMT with a single‐exponential time constants of 114.2 ± 6.5 min for HMT–dT 17 adducts and 677.8 ± 181.8 min for HMT–dA 7 TTA 8 adducts. Our results show that fluorescent MB probes are a selective, robust and accurate tool for detecting UVA‐activated HMT‐induced DNA damage.