Photocleavage of DNA: irradiation of quinone-containing reagents converts supercoiled to linear DNA.
Irradiation (350 nm) of air-saturated solutions of reagents containing an anthraquinone group linked to quaternary alkyl ammonium groups converts supercoiled DNA to circular and to linear DNA. Generation of linear DNA does not occur by accumulation of numerous single-strand cuts but by coincident-site double-strand cleavage of DNA. Irradiation forms the triplet state of the anthraquinone, which reacts either by hydrogen atom abstraction from a sugar of DNA or by electron transfer from a base of the DNA. Subsequent reactions result in chain scission. The quinone is apparently reformed after this sequence and reirradiation leads to double-strand cleavage.
Koch
T
T
Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana 61801.
Ropp
J D
JD
Sligar
S G
SG
Schuster
G B
GB
D004249:DNA Damage; D004278:DNA, Superhelical / Q000187:drug effects*; D010782:Photolysis; D010957:Plasmids / Q000187:drug effects*; D011809:Quinones / Q000494:pharmacology* / Q000528:radiation effects*; D014466:Ultraviolet Rays
D004278:DNA, Superhelical; D011809:Quinones