TABLE 1.

Free energy changes for hybridization between a hairpin (l = 21, n = 16) and opening strands with different toeholds

Toehold length, position	Fraction hybridized*	(kcal mol−1)†	(kcal mol−1)‡	(kcal mol−1)
5, e	0.88	−13.9	−8.2	5.7
4, e	0.67	−12.4	−6.8	5.6
3, e	0.38	−11.3	−4.6	6.7
5, i	0.86	−13.5	−8.9	4.6
4, i	0.73	−12.7	−6.7	6.0
3, i	0.47	−11.7	−5.3	6.4

^*The fraction hybridized is deduced from steady-state donor fluorescence from a dual-labeled opening strand.

^†Corresponds to the measured equilibrium constant.

^‡Calculated using nearest-neighbor model (11).