. 2012 Jun 20;102(12):2799–2807. doi: 10.1016/j.bpj.2012.05.014

Table 3.

Displacements and actin-detachment kinetics for myo1b^IQ and myo1b^a,^∗

	− Calcium		+ Calcium
	Myo1b^IQ	Myo1b^a	Myo1b^IQ	Myo1b^a
Total (nm)	5.2 ± 0.63	13 ± 0.57	1.1 ± 0.47	0.89 ± 0.34
Step 1 (nm)	4.2 ± 0.53	6.5 ± 0.53	0.72 ± 0.48	0.17 ± 0.39
Step 2 (nm)	1.0 ± 0.82	6.5 ± 0.78	0.38 ± 0.67	0.72 ± 0.52

Actin detachment rates for myo1b^IQ and myo1b^a,^∗

	− Calcium		+ Calcium
	Myo1b^IQ	Myo1b^a	Myo1b^IQ	Myo1b^a
k_det (s⁻¹)	1.1 ± 0.023	0.23 ± 0.0040	2.6 ± 0.049	1.7 ± 0.011

Calcium dependence of Myo1b-IQ and Myo1b^a force sensitivity^∗,†,‡

	− Calcium		+ Calcium
	Myo1b^IQ	Myo1b^a	Myo1b^IQ	Myo1b^a
k_g₀ (s⁻¹)	0.77 +0.12/−0.27	0.62 +0.49/−0.24	1.5 +0.59/−0.34	0.67 +0.13/−0.13
k_i (s⁻¹)	NA	0.014 +0.0044/−0.0034	NA	NA
d_det (nm)	4.1 +0.39/−1.1	21 +5.5/−5.1	0.96 +0.75/−0.81	2.9 +0.51/−0.46

^∗

Performed in the optical trap in KMg25 the presence of 25 μM ATP ± 9 μM Ca²⁺_F at 20°C.

^†

Force was applied with an isometric optical clamp (see Materials and Methods).

^‡

Fit to a probability distribution function and optimized with an MLE routine; 90% confidence interval, N = 1000 simulations (see Materials and Methods).