Table 2.

Microtubule equilibrium binding constants for kinesin-5

Ionic strength	Eg5		Cin8-Trx		Cin8-His		Cin8-His (ATP)
	21 mm	88 mm	21 mm	88 mm	21 mm	88 mm	21 mm	88 mm
Kd, app (μm)a	0.014 ± 0.007	0.50 ± 0.22	0.001 ± 0.003	0.13 ± 0.39	0.26 ± 0.15	0.18 ± 0.12	0.14 ± 0.06	0.96 ± 0.45
CIMSE (μm)b	0.005–0.029	0.36–5.37	<1 × 10−6–0.04	0.06–0.25	0.01–0.63	0.01–0.23	0.02–0.62	0.44 to>1000
sc	1.1 ± 0.7	1.4 ± 0.7	5.1 ± 4.2	4.0 ± 3.3	3.1 ± 0.6	3.0 ± 1.0	3.7 ± 2.1	6.1 ± 4.8
CIMSE	1.07–1.19	0.85–5.85	4.68–5.71	3.35–4.95	2.66–7.85	2.42–4.19	2.66–7.85	2.58 to >100

^a Average fit constants when stoichiometry coefficient (s) held fixed to 1 for Eg5 and floated for Cin8 ± standard deviation of the mean is shown. n = 3–6 experimental data sets for each condition.

^b CI_MSE is the asymmetric confidence interval determined from our MSE analysis.

^c Stoichiometry coefficient (s) was determined by floating both K_{d, app} and s in Equation 3 using nonlinear least squares fitting in Mathematica.