Figure 1.

(A) Gel electrophoresis of dA₁₅ showing two forms with different electrophoretic mobility. P³² labeled dA₁₅ was incubated at the indicated pH at 4°C and then electrophoresed on 15% native PAGE in Robinson–Britton buffer of corresponding pH at 20°C and visualized using PhosphorImager. pH values are indicated above each lane (Na⁺ = 30 mM). (B) CD spectra of 1 μM dA₁₅ at pH 3.0 and pH 7.0 in 10 mM phosphate recorded at both 20°C and 95°C (Na⁺ = 10 mM). Inset: CD at 217 nm of 5 µM dA₁₅ in 10 mM Na⁺ cation as a function of buffer pH.