Table 2.

The parameters k₊/k₋ and k_off calculated for nanoparticles and KIF1A

Charged nanoparticle						KIF1A
Q	k+/k–∗	koff (s−1)†	τdur (ms)‡	τA (ms)§	Diffusion length (nm)¶	No. of lysine in K-loop	k+/k–‖	koff (s−1)∗∗	τdur (ms)††	τA (ms)‡‡	Diffusion length (nm) ¶
13	0.273	58.4	63	17.1	227	1	0.0015	3333	200	0.3	93
15	0.223	45.9	98	21.8	256	2	0.0015	1481	450	0.7	140
24	0.091	15.6	707	64.1	439	4	0.0015	635	1050	1.6	214
26	0.074	12.3	1098	81.5	495	6	0.0015	95	7000	10.5	553
32	0.041	6.0	4109	167.5	709
42	0.015	1.8	37084	556.1	1292

^∗$k_{+}/k_{-}\cong e^{-Q\Delta E_1/k_{\text{B}}T}$, where ΔE₁ = 0.1 k_BT.

^†$k_{\text{off}}\cong {\tau }_{00}^{-1}{e}^{-Q\left(\Delta E_2-\Delta E_1\right)/k_{\text{B}}T}$, where ΔE₂–ΔE₁ = 0.12 k_BT and τ₀₀ = 3.6 ms.

^‡${\tau }_{\mathrm{dur}}^{-1}={\tau }_{00}^{-1}{e}^{-Q\Delta E_2/k_{B}T}$, where ΔE₂ = 0.22 k_BT, τ₀₀ = 3.6 ms.

^§τ_A = k_off⁻¹.

^¶Diffusion length was estimated as ${\left(D_0{\tau }_{\text{A}}\right)}^{1/2}$, where D₀ = 3 μm²/s and 28 μm²/s for nanoparticle and KIF1A, respectively.

^‖$k_{+}/k_{-}\cong e^{-\Delta E_1/k_{\text{B}}T}$, where ΔE₁ = 6.5 k_BT. See Appendix B for detail.

^∗∗k_off = τ_A⁻¹.

^††Numbers taken from Fig. 3B in Okada and Hirokawa (14).

^‡‡${\tau }_{\text{A}}={\tau }_{\text{dur}}{e}^{-6.5}$.