Families of basepairs involving Shallow-Groove Edge. Families of basepairs involving only Watson-Crick and Hoogsteen Edges. These result in Bifurcated and Water-Inserted pairings. Bifurcated Pairings 2. Due to the complexity of RNA structure, it is very hard to represent tertiary motifs in 2D drawings.
Tertiary motifs consist largely of non-canonical pairings.