Isolation and characterization of a new product produced by ionizing irradiation and type I photosensitization of 2'-deoxyguanosine in oxygen-saturated aqueous solution: (2S)-2,5'-ANHYDRO-1-(2'-deoxy-beta-D-erythro-pentofuranosyl)-5-guanidin ylidene- 2-hydroxy-4-oxoimidazolidine.
A major product of the radiation-induced decomposition of 2'-deoxyguanosine in oxygen-saturated aqueous solution has been isolated by reverse phase high performance liquid chromatography and characterized by carbon and proton NMR spectroscopy, fast-atom bombardment mass spectrometry, and chemical analysis as (2S)-2,5'-anhydro-1-(2'-deoxy-beta-D-erythro-pentofuranosyl)-5-guanid inylidene- 2-hydroxy-4-oxoimidazolidine(d < G). This compound is stable in aqueous solution at room temperature but decomposes upon heating (45 degrees C). The lesion is also observed following type I (riboflavin, benzophenone, and acetophenone) photosensitized irradiation of 2'-deoxyguanosine at 350 nm in oxygen-saturated aqueous solution. A similar reaction mechanism, involving a neutral guanine radical intermediate, is proposed to explain the generation of d < G following both types of irradiation.
Buchko
G W
GW
Department of Radiobiology, Cross Cancer Institute, Edmonton, Alberta, Canada.
Cadet
J
J
Ravanat
J L
JL
Labataille
P
P
D000098:Acetophenones / Q000494:pharmacology; D001577:Benzophenones / Q000494:pharmacology; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000528:radiation effects*; D048289:Imidazolidines; D010100:Oxygen; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012256:Riboflavin / Q000494:pharmacology; D012996:Solutions; D014867:Water
D000098:Acetophenones; D001577:Benzophenones; D048289:Imidazolidines; D017319:Photosensitizing Agents; D012996:Solutions; D014867:Water; C081842:2,5'-anhydro-1-(2'-deoxy-beta-erythro-pentofuranosyl)-5-guanidinylidene-2-hydroxy-4-oxoimidazolidine; C047723:benzophenone; D003849:Deoxyguanosine; C038699:acetophenone; D010100:Oxygen; D012256:Riboflavin