∆G°37 =
∆G°37(Watson-Crick Pairs) + ∆G°37(Hairpin Loop)
∆G°37 = ∆G°37(Watson-Crick Pairs) + ∆G°37(terminal mismatch) + ∆G°37 Hairpin initiation(6)
∆G°37 = ∆G°37(CG followed by AU) + ∆G°37(AU followed by CG) + ∆G°37(CG followed by AU) + ∆G°37 AU end penalty + ∆G°37(AU followed by AA) + ∆G°37 Hairpin initiation(6)
∆G°37 =
–2.11 kcal/mol – 2.24 kcal/mol – 2.11 kcal/mol + 0.45 kcal/mol – 0.8 kcal/mol
+
5.4 kcal/mol
∆G°37 =
–1.4 kcal/mol
Note that for unimolecular secondary structures, the helical intermolecular initiation does not appear.