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PHOTOADDUCTS OF 8‐METHOXYPSORALEN TO CYTOSINE IN DNA
Author(s) -
Calvin Noel M.,
Hanawalt Philip C.
Publication year - 1987
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.1751-1097.1987.tb05382.x
Subject(s) - cytosine , thymine , adduct , chemistry , isomerization , dna , stereochemistry , oligonucleotide , photochemistry , biochemistry , organic chemistry , catalysis
— The isolation and partial characterization of several photoadducts formed between 8‐methoxypsoralen (8‐MOP) and cytosine is described. The formation of these adducts was analysed in E. coli DNA containing 3 H‐labeled cytosine and/or 14 C‐labeled thymine, and in oligonucleotides of defined sequence. The major initial adduct has been identified as an 8‐MOP cytosine monoadduct, most likely forming at the pyrone end of the 8‐MOP molecule. Further irradiation converts this adduct to several other species, including both cytosine:cytosine and cytosine:thymine diadducts, as well as a number of derivative monoadducts. One isomer of the C:T diadduct appears to undergo a reversible isomerization under the conditions normally used to analyse adduct mixtures by HPLC. The isomerization can cause this adduct to exhibit a retention time on reversed‐phase HPLC closely resembling either that of a thymine‐thymine crosslink or a thymine monoadduct.