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PHOTOCHEMICAL INTERACTION BETWEEN XANTHYLETINE AND DNA
Author(s) -
Dall'acqua F.,
Bordin F.,
Vedaldi D.,
Recher M.,
Rodighiero G.
Publication year - 1979
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.1751-1097.1979.tb07050.x
Subject(s) - dna , covalent bond , psoralen , chemistry , double bond , reagent , stereochemistry , ring (chemistry) , photochemistry , biophysics , biochemistry , biology , organic chemistry
— Xanthyletine, a dimethyl‐pyranocoumarin having a structural relationship to psoralen, has been studied in connection with its interaction with DNA. In the dark, it forms a weak molecular complex with DNA, which is not of the intercalated type. Under irradiation at 365nm, it is able to bind covalently to DNA, with, however, a much lower rate relative to psoralen. In this photobinding, it behaves as a pure monofunctional reagent, involving only its 3 ,4‐double bond of the α‐pyronic ring. 3‐(α,α‐dimethyl‐allyl)‐xanthyletine, studied for a comparison, showed only a very low photoreactivity with DNA for covalent addition; this is attributed to the presence of a bulky group at position 3 , which prevents almost completely the photoreaction of the 3 ,4‐double bond. Because of the low capacity of photobinding with DNA and the inability to form cross‐links, the photobiological effects of xanthyletine are accordingly reduced: Inhibition of DNA and RNA synthesis in Ehrlich ascites tumor cells, killing of E. coli bacterial cells, inactivation of T 2 bacteriophage have been observed. By contrast, it was inactive in producing erythema on guinea pig skin.