title: Tryptophan photoproduct(s): sensitized induction of strand breaks (or alkali-labile bonds) in bacterial deoxyribonucleic acid during near-ultraviolet irradiation.
abstract: Long-wavelength ultraviolet light (300 to 400 nm) converts L-tryptophan to a photoproduct that is toxic for bacterial cells in dark conditions. We now report that similar photoproducts of l-tryptophan sensitize bacterial deoxyribonucleic acid to 365-nm radiation, increasing the yield of deoxyribonucleic acid strand breaks (or alkali-labile bonds) by approximately 11.5-fold. Evidence is also presented which indicates that thse sensitized deoxyribonucleic acid lesions contribute to lethality for Escherichia coli irradiated with 365-nm ultraviolet light in suspensions of tryptophan photoproducts.
mesh_terms: D004260:DNA Repair / Q000528:radiation effects; D004269:DNA, Bacterial / Q000378:metabolism / Q000528:radiation effects*; D004926:Escherichia coli / Q000378:metabolism / Q000528:radiation effects*; D009691:Nucleic Acid Denaturation; D011830:Radiation Effects; D014364:Tryptophan / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D014364:Tryptophan