Table 1.

Distance to the transition state from isoI (Δx_f^‡) and from isoII (Δx_b^‡) measured from the force-dependent transition rates between isoI and isoII for four different junctions. Errors represent standard deviation from five different molecules each. Also shown is Δx_eq, the distance between isoI and isoII determined from force-dependent changes in the equilibrium constant. For junction BR, Δx_eq deviates significantly from (Δx_b^‡+Δx_f^‡) showing that d_BR is not a valid reaction coordinate connecting isoI and isoII. In contrast, Δx_eq=Δx_b^‡+Δx_f^‡ within error for junctions XR and HR showing that d_XR and d_HR are reaction coordinates valid from isoI to isoII.

	XR	XR-long	HR	BR
Δxb‡ (nm)	1.5 (±0.3)	2.6 (±0.6)	2.4 (±0.5)	1.1 (±0.2)
Δxf‡ (nm)	2.9 (±0.6)	7.7 (±1.5)	1.3 (±0.3)	0.37 (±0.2)
Δxeq (nm)	4.4 (±0.8)	9.9 (±2.6)	3.1 (±0.8)	0.7 (±0.2)
Δxb‡+Δxf‡ (nm)	4.4 (±0.8)	10.3 (±2.0)	3.6 (±0.5)	1.5 (±0.3)