Figure 3.

Circular dichroism (CD) study of the effect of urea on the RNAs used in this work. A: A red shift in the CD peak at ~260 nm is observed with increasing urea concentration for all the RNA strands. B: The ability of increasing the urea concentration to induce structural changes within the RNA in bulk solution correlates with the gradient of the traces in Panel A (i.e., dλ/d[urea], given in nm.M ⁻¹), which decreases with increasing strand length. Experimental conditions: 1 M KCl, 20 mM Tris.HCl, pH 7.50, at an RNA concentration of 24 μg mL ⁻¹.