Regulation of DNA duplex formation by hypoxic irradiation: one-electron reduction characteristics of oligodeoxynucleotides possessing 2-oxoalkyl functional group.

We synthesized oligodeoxynucleotides (ODN) possessing 2-oxoalkyl group on thymidine (d(oxo)T) to characterize the radiolytic reduction in aqueous solution. Corresponding unmodified ODNs were generated from ODNs containing d(oxo)T upon hypoxic irradiation. Enzymatic digestion of the duplex consisting of the hypoxically irradiated ODN containing d(oxo)T and its complementary strand resulted in an efficient cleavage, but no cleavage was observed when a control duplex was digested without irradiation.