A Phototautomerizable Model DNA Base Pair

J. Am. Chem. Soc., 122 (41), 9917 -9920, 2000. 10.1021/ja001778n S0002-7863(00)01778-9
Web Release Date: October 3, 2000

A Phototautomerizable Model DNA Base Pair

Anthony K. Ogawa, Osama K. Abou-Zied, Vickie Tsui, Ralph Jimenez, David A. Case, and Floyd E. Romesberg*

Contribution from the Departments of Chemistry and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037

Received May 22, 2000

Abstract:

2-(2'-Hydroxyphenyl)benzoxazole (HBO) undergoes rapid photoinduced proton transfer from the enol-imine to the keto-amine tautomer. When incorporated in duplex DNA opposite an abasic site, HBO appears to be a good mimic of a natural DNA base pair based on duplex stability, UV and CD spectroscopy, and molecular dynamics simulations. In the chosen sequence context, HBO exists exclusively as the syn-enol tautomer, which is consistent with an environment of the model base that is dominated by neighboring nucleobases and not by solvation. The syn-enol efficiently undergoes photoinduced proton transfer to the keto-tautomer, which should allow for the study of tautomerization within the duplex DNA.

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