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Updated: Jan 20, 2026

Mapping RNA-RNA Interactions Globally Using Biotinylated Psoralen
Published on: May 24, 2017
The Photoaddition of a Psoralen to DNA Proceeds via the Triplet State
Janina Diekmann1, Julia Gontcharov2, Sascha Fröbel1
1Institut für Physikalische Chemie , Heinrich-Heine-Universität Düsseldorf , Universitätsstr. 1 , 40225 Düsseldorf , Germany.
Abstract:
Psoralens are natural compounds that serve in the light dependent treatment of certain skin diseases (PUVA therapy). They are DNA intercalators that upon photoexcitation form adducts with thymine bases. For one psoralen derivative, 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT), the photoreactions are characterized here by nanosecond UV-vis and IR absorption spectroscopy. The triplet state of AMT is identified as the reactive one. On the 1-10 μs time scale this local triplet state transforms into a triplet biradical bearing one single bond between the addends. Within ∼50 μs this biradical forms the final adduct featuring a cyclobutane ring. This kinetic behavior is in stark contrast to the closely related photoaddition of two thymine moieties within the DNA. Origins of the differences are discussed.
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