Parameter:	ΔG°37 loop (kcal/mol)
Initiation, n=1	+3.8 ± 1.1
Initiation, n=2	+2.8 ± 1.3
Initiation, n=3	+3.2 ± 1.9
Initiation, n=4	+3.6
Initiation, n=5	+4.0
Initiation, n=6	+4.4