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FLUORESCENCE QUANTUM YIELD DETERMINATION OF PYRIMIDINE (6‐4) PYRIMIDONE PHOTOADDUCTS
Author(s) -
Blais J.,
Douki T.,
Vigny P.,
Cadet J.
Publication year - 1994
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.1751-1097.1994.tb05055.x
Subject(s) - thymine , thymidine , chemistry , pyrimidine , phosphodiester bond , fluorescence , dna , quantum yield , stereochemistry , uracil , biochemistry , rna , physics , quantum mechanics , gene
An extensive study of the fluorescence characteristics of pyrimidine (6‐4) pyrimidone photoadducts, a major class of far‐UV‐induced DNA lesions, was carried out on dinucleoside monophosphate (6‐4) photoadducts, including thymidylyl‐(3’→ 5′)‐thymidine (TpT), 2′‐deoxycytidylyl‐(3′‐5′)‐thymidine, thymidylyl‐(3’→ 5′)‐2′‐deoxy‐cytidine, 2′‐deoxyuridylyl‐(3’→ 5′)‐thymidine, 5‐methyl‐2′‐deoxycytidylyl‐(3′‐5′)‐thymidine (6‐4) photoadducts and the corresponding base (6‐4) photoadducts, 6‐4′‐(5′‐methylpyrimidin‐2′‐one) thymine (TT), 5‐hydroxy‐6‐4′‐(5′‐methylpyrimidin‐2′‐one)‐5,6‐dihydrothymine (CT), 5‐amino‐6‐4′‐(pyrimidin‐2′‐one)‐5,6‐dihydrothymine (UC) obtained by mild acidic hydrolysis of the former derivatives. The fluorescence quantum yield (Φ F ) of these compounds was found to depend on one hand, on the nature of the two bases involved and the base substituent and, on the other hand, on the presence of the phosphate group. The hydrolysis of the phosphodiester bond was shown to enhance Φ F , the larger effect being observed in the case of the thymine‐thymine photoadducts with a seven‐fold increase of the Φ F value in the case of TT as compared to TpT (0.21 and 0.03, respectively). These results are discussed in terms of structural considerations.