Singlet oxygen mediated photobinding of 8-methoxypsoralen to DNA and genotoxicity in E. coli.
Although oxygen dependent photoreactions of 8-methoxypsoralen (8-MOP) are known, damage to DNA is mostly considered to proceed via photocycloaddition to this biomacromolecule. In this study the survival of colony forming ability of E. coli K12/343, which is deficient in DNA-repair capability, appeared to be lower in D2O than in H2O after exposure to the combination of 8-MOP and UV-A. Photobinding to bacterial DNA was approximately 40% higher in D2O than in H2O. However this last difference was found only when the bacteria were kept in the reaction medium for 1 h at 37 degrees C after the irradiation was stopped and not when they were plated out immediately afterwards. The results indicate that in this bacterial test system 1O2 mediated photobinding of 8-MOP to DNA contributes to the genotoxic effect observed.
Beijersbergen van Henegouwen
G M
GM
Department of Pharmacochemistry, Leiden University, The Netherlands.
Wijn
E T
ET
Schoonderwoerd
S A
SA
de Vries
H
H
Dall'Acqua
F
F
D004260:DNA Repair; D004269:DNA, Bacterial / Q000378:metabolism* / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects*; D007700:Kinetics; D008730:Methoxsalen / Q000378:metabolism* / Q000494:pharmacology; D010100:Oxygen; D010777:Photochemistry; D026082:Singlet Oxygen; D014466:Ultraviolet Rays
D004269:DNA, Bacterial; D026082:Singlet Oxygen; D010100:Oxygen; D008730:Methoxsalen