Interconversion of the cis-5R,6S- and trans-5R,6R-thymine glycol lesions in duplex DNA.

ABSTRACT: Thymine glycol (Tg), 5,6-dihydroxy-5,6-dihydrothymine, is formed in DNA by the reaction of thymine with reactive oxygen species. The 5R Tg lesion was incorporated site-specifically into 5'-d(G(1)T(2)G(3)C(4)G(5)Tg(6)G(7)T(8)T(9)T(10)G(11)T(12))-3'; Tg = 5R Tg. The Tg-modified oligodeoxynucleotide was annealed with either 5'-d(A(13)C(14)A(15)A(16)A(17)C(18)A(19)C(20)G(21)C(22)A(23)C(24))-3', forming the Tg(6) x A(19) base pair, corresponding to the oxidative damage of thymine in DNA, or 5'-d(A(13)C(14)A(15)A(16)A(17)C(18)G(19)C(20)G(21)C(22)A(23)C(24))-3', forming the mismatched Tg(6) x G(19) base pair, corresponding to the formation of Tg following oxidative damage and deamination of 5-methylcytosine in DNA. At 30 degrees C, the equilibrium ratio of cis-5R,6S:trans-5R,6R epimers was 7:3 fo

SUBMITTER: Brown KL 

PROVIDER: S-EPMC2646635 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature