Synthesis of DNA single strand-containing 15N labeled cis-syn thymine dimer

ORGN 503

Hussam M. Bdour and John-Stephen A. Taylor. Department of Chemistry, Washington University, Campus Box 1134, One Brookings Drive, St. Louis, MO 63130-4899
Cis-syn thymine dimers are the major photoproducts of DNA and are the principal cause of mutations induced by sunlight. To better understand the nature of base pairing with cis-syn thymine dimers we have synthesized 10-mer oligodeoxynucleotides (ODNs) containing a cis-syn dimer of TT labeled at N3 of both Ts. The ODNs were synthesized by two methods from 15N-labeled thymidine. In the first method an ODN containing an 15N-labeled TT site was irradiated and the cis-syn dimer isolated by HPLC. In the second method, an 15N-labeled cyclobutane thymine dimer phosphoramidite building block was first prepared and used to introduce the dimer into the ODN by solid phase automated automated synthesis.