- Main Article: Base Pairing
Bases interact with one another by hydrogen bonding and stacking. These interactions help stabilize folded RNA structures. In EteRNA, three types of base pairs are encountered: AU pairs, GC pairs, and GU pairs.
|R||Adenine or Guanine (Purine Bases)|
|Y||Cytosine or Uracil (Pyrimidine Bases)|
|M||Adenine or Cytosine (Amino Bases)|
|K||Uracil or Guanine (Keto Bases)|
Bases can exist in different structural isomers known as tautomers. In each case, one tautomer is heavily favored over others. The ability to shift between tautomeric forms is important in the formation of certain noncanonical base pairs and contributes mutation during replication of RNA and DNA.