Figure 1.

(A) CD spectra of 10 μM H12 and H24 DNA in the solutions containing 150 mM of Na⁺ or K⁺ cation. (B) CD spectra of 20 μM H24 in 150 mM Na⁺ solution upon K⁺ titration. Each CD spectrum was recorded right after the K⁺ titration.