Photochemical control of DNA structure through radical disproportionation.

ABSTRACT: Photolysis of an aryl sulfide-containing 5,6-dihydropyrimidine (1) at 350 nm produces high yields of thymidine and products resulting from trapping of a 5,6-dihydrothymidin-5-yl radical by O₂ or thiols. Thymidine is believed to result from disproportionation of the radical pair originally generated from C--S bond homolysis of 1 on the microsecond timescale, which is significantly shorter than other photochemical transformations of modified nucleotides into their native forms. Duplex DNA containing 1 is destabilized, presumably due to disruption of π-stacking. Incorporation of 1 within the binding site of the restriction endonuclease EcoRV provides a photochemical switch for turning on the enzyme's activity. In contrast, 1 is a substrate for endonuclease VIII and serves as a photochemical o

SUBMITTER: San Pedro JM 

PROVIDER: S-EPMC3807129 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature