Figure 1.

(a) Randomly generated structure of length 75 (RND-75-n62) with loops separated by short stems. The line represents the location where the structure is split into two substructures. Parts (b) and (c) show the corresponding substructures with a static cap structure and dangling ends, respectively. Parts (d) and (e) show the same substructures with a dynamic cap structure and dynamic dangling ends, respectively.