The Stability of a Model Substrate for Topoisomerase 1-Mediated DNA Religation Depends on the Presence of Mismatched Base Pairs

Figure 2

Stability of the 39 mer DNA hairpin corresponding to a model Top1 cleavage site. A single coordinated transition is observed corresponding to the thermal melting transition for the double-stranded region of the hairpin. As expected, the melting temperature is dependent upon the presence of a mismatched base pair at the terminus of the duplex region. The native sequence is most stable while C → T, C → dU, and C → FdU decrease the stability of the duplex region by 4.4°C, 3.0°C, and 3.5°C, respectively.