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Summer 2006 Bioanalytical Science REU Participants

Jasmina Cheung-Lau, Amherst College

THE APPLICATION OF 5-PHENYLTHIO-2'-DEOXYURIDINE FOR THE PREPARATION OF DUPLEX DNA WITH EXTENDED p SYSTEM

 

Jasmina C. Cheung-Lau , Yu Zeng, Yinsheng Wang
Department of Chemistry, University of California - Riverside, UCR 92521 and Amherst College, Amherst, MA, 01002.

The synthesis of 5-phenylthio-2'-deoxyuridine (dPhSU) and its photocyclization chemistry has been reported in an earlier study1. Here, we describe the preparation of a decameric duplex DNA carrying the cyclic product, d(PhS U*). We first purified d(ATGGCAPhSUGCT) by HPLC, irradiated it with UVC light, and separated the resulting mixture again by HPLC. ESI-MS and MS/MS was used to confirm the presence of the cyclic product: d(ATGGCAPhSU*GCT). We then annealed the d(PhSU*)-bearing decamer with a complementary strand and measured the melting temperature of the duplex with a UV-vis spectrophotometer. During this process, we used three different complementary strands, with the complementary base of PhSU* being A, G, or C. For each run, three different samples would be used, all containing the same complementary strand. This step was necessary for comparison of the melting temperatures; the samples were: d(ATGGCAXGCT), where X is a dT, d(PhSU), or d(PhSU*). From the resulting UV melting curves and the reported melting temperatures, we came to two conclusions: first, the cyclic product 10-mer anneals best with the A-containing complementary strand. Second, we found that the dPhSU*)-containing duplex, though more stable than the d(PhSU)-containing double helix, is less stable than the corresponding unmodified duplex DNA.

1Zeng, Y.; Cao, H.; Wang, Y. Org. Lett. 2006, 8, 2527-30.

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