Table 3.

Comparison of measured FRET efficiencies.^a

	[GdmCl]
	2 M	2.25 M	2.5 M
$E_{1\text{F}}^{\text{2c}}$	0.83	0.83	0.81
$E_{1\text{F}}^{\text{3c}}$	0.85 (±0.01)	0.83 (±0.01)	0.81 (±0.01)
$E_{1\text{U}}^{\text{2c}}$	0.66	0.65	0.64
$E_{1\text{U}}^{\text{3c}}$	0.72 (±0.01)	0.69 (±0.01)	0.68 (±0.01)
$E_{1\text{U}}^{\text{G}}$	0.73	0.69	0.67
$E_{\text{2F}}^{\text{2c}}$	0.29	0.29	0.31
$E_{\text{2F}}^{\text{3c}}$	0.30 (±0.09)	0.20 (±0.09)	0.51 (±0.06)
$E_{\text{2U}}^{\text{2c}}$	0.20	0.20	0.19
$E_{\text{2U}}^{\text{3c}}$	0.42 (±0.02)	0.21 (±0.03)	0.16 (±0.03)
$E_{\text{2U}}^{\text{G}}$	0.17	0.15	0.14

^aErrors for the three-color FRET efficiencies are obtained from the propagation of the errors (standard deviations) calculated from the curvature at the maximum of the likelihood function.