Figure 7.

Proposed folding mechanism. Secondary structures were predicted by the Vienna RNA server.^5,42 The red set of states has a non-native secondary structure but includes both open (low-FRET) tertiary structures and compact (high-FRET) tertiary structures. The blue set of states has the native secondary structure but also includes both open and compact tertiary structures. Compact structures in the red and blue sets are stabilized by Mg²⁺. The black state has the native secondary and tertiary fold. In contrast to the compact blue state, it is additionally stabilized by the tertiary Watson–Crick pairs that form the pseudoknot.