Premium
BENZOPHENONE PHOTOSENSITIZATION OF 2′‐DEOXYGUANOSINE: CHARACTERIZATION OF THE 2R AND 2s DIASTEREOISOMERS OF 1‐(2‐DEOXY‐β‐D‐ erytho W‐PENTOFURANOSYL)‐2‐METHOXY‐4,5‐IMIDAZOLIDINEDIONE. A MODEL SYSTEM FOR THE INVESTIGATION OF PHOTOSENSITIZED FORMATION OF DNA‐PROTEIN CROSSLINKS
Author(s) -
Morin Benedicte,
Cadet Jean
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.tb05074.x
Subject(s) - benzophenone , diastereomer , chemistry , deoxyguanosine , guanine , methanol , circular dichroism , nuclear overhauser effect , stereochemistry , derivative (finance) , photochemistry , nuclear magnetic resonance spectroscopy , nucleotide , organic chemistry , adduct , biochemistry , financial economics , economics , gene
Benzophenone‐mediated photosensitization of 2′‐deoxyguanosine and its 3′,5′‐di‐O‐acetyl derivative, used as DNA model compounds, in oxygen‐saturated water‐methanol (1:1) solution results in the nucleophilic addition of methanol to the guanine base. The resulting modified nucleosides have been isolated by reverse‐phase high‐performance liquid chromatography and characterized by extensive spectroscopic measurements including 13 C and I H nuclear magnetic resonance, fast atom bombardment mass spectrometry and circular dichroism as the 2R and 2s diastereoisomers of 1‐(2‐deoxy‐˜‐o‐erythro‐pentofuranosyl)‐2‐methoxy‐4,5‐imidazolinedione and their related 3′,5′‐di‐O‐acetyl derivates. Information concerning the absolute configuration of the two pairs of diastereoisomers was inferred from detailed nuclear Overhauser effect experiments. A reaction mechanism, involving guanine radical intermediates, is proposed to explain the generation of these new guanine photoproducts.