Figure 4.

CD spectra of duplex (dA)₁₆·(dT)₁₆ samples that illustrate duplex disproportionation. (A) Duplex (dA)₁₆·(dT)₁₆ sample with and without added coralyne at 4°C prior to heating. (B) Spectra of duplex (dA)₁₆·(dT)₁₆ samples with and without coralyne at 36°C. (C) Heat-cycled spectrum of disproportioned (dA)₁₆·(dT)₁₆ sample in the presence of coralyne at 4°C and composite spectrum {sum of spectra acquired at 4°C: [0.50 × triplex (dA)₁₆·(dT)₁₆·(dT)₁₆ with 0.25 molar equivalents of coralyne] + [0.50 × single stranded (dA)₁₆ with 0.25 molar equivalents of coralyne]}. (D) Spectra of (dA)₁₆ sample with and without coralyne at 4°C. DNA concentrations were 55 µM nucleotide or base pair, respectively. Coralyne concentration was 0.25 molar equivalents per nucleotide or base pair, respectively.