Photosensitized [2 + 2] cycloaddition of N-acetylated cytosine affords stereoselective formation of cyclobutane pyrimidine dimer.

ABSTRACT: Photocycloaddition between two adjacent bases in DNA produces a cyclobutane pyrimidine dimer (CPD), which is one of the major UV-induced DNA lesions, with either the cis-syn or trans-syn structure. In this study, we investigated the photosensitized intramolecular cycloaddition of partially-protected thymidylyl-(3'→5')-N(4)-acetyl-2'-deoxy-5-methylcytidine, to clarify the effect of the base modification on the cycloaddition reaction. The reaction resulted in the stereoselective formation of the trans-syn CPD, followed by hydrolysis of the acetylamino group. The same result was obtained for the photocycloaddition of thymidylyl-(3'→5')-N(4)-acetyl-2'-deoxycytidine, whereas both the cis-syn and trans-syn CPDs were formed from thymidylyl-(3'→5')-thymidine. Kinetic analyses revealed that the act

SUBMITTER: Yamamoto J 

PROVIDER: S-EPMC3035463 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature