cartoons of an RNA loop in various folded states Observed unfolding pathway. The phosphate-ribose backbones of the stem are displayed as black sticks for clarity, with the loop backbone and bases colored (from 5' to 3': G5 in red, C6 in blue, A7 in green, and A8 in red). The lower panel of images shows each structure rotated ~90° to display helicity (or lack thereof) within each structure. from Sorin et al, JMB 317:493