Figure 1.

CD spectra for the DNA constructs shown in Scheme 1: spectra for the native (solid lines, 0 °C) and denatured (stippled lines, 95 °C) Ω-DNA constructs with and without F abasic site lesion. The unmodified parent sequence is shown in black, whereas the spectrum of the Ω-DNA with the lesion upstream of the loop domain (CAG-FStem) is shown in red and that of the lesion downstream of the loop (CTG-FStem) is in green. The spectra of the constructs with the lesion in the loop domain are shown in magenta (CAG-F1), blue (CAG-F3), and purple (CAG-F5). Note the overall similarities in the native spectra at 0 °C, indicating that the global structure is not significantly perturbed by the F lesion.