TABLE 1.

Rate constants for the kinesin-5 chemomechanical cycle

State	Rate constant	Description	Source	Experiment	Units
1-2	kbind	Bound-head Mt on-rate	Fig. 4c	4.2 ± 0.2	μm−1 s−1
2-1	kunbind	Bound-head Mt off-rate	Fig. 2f	0.77 ± 0.06	s−1
2-3	koffADP	Bound-head ADP off-rate	Fig. 1b	37.8 ± 5.3	s−1
3-4	konATP	Bound-head ATP on-rate	Fig. 1e	1.5 ± 0.2	μm−1 s−1
4-5	khyd	Hydrolysis rate	Deriveda	250 (79, 414)b	s−1
5-1	kunbindDP	Mt off-rate at ADP-Pi state	Deriveda	21.3 ± 4.5	s−1
5-6	kattach	Front-head attachment rate	Deriveda	476 (79, 1073)b	s−1
6-7	koff,FHADP	Front-head ADP off-rate	Fig. 4a	75 ± 8	s−1
7-6	kon,FHADP	Front-head ADP on-rate	Fig. 4a	2.1 ± 0.8	μm−1 s−1
6-2	kdetach	Trailing-head detachment rate	Derivedc	10.1 ± 0.3	s−1
7-3	kdetach
8-4	kdetach
7-8	kon,FHATP	Front-head ATP on-rate	Fig. 4b	0.28 ± 0.08	μm−1 s−1
8-7	koff,FHATP	Front-head ATP off-rate	Fig. 4b	92 ± 2	s−1

^a In Fig. 1, c and d, 1/k_cat − 1/ k_off^ADP = 1/k_hyd + 1/ k_unbind^DP = 51 ± 10 ms. In Figs. 3c and 4a, 1/k_max^ATP/HS − 1/k_FH,off^ADP = 1/k_hyd + 1/k_attach = 5.6 ± 1.6 ms. In Fig. 2c, processivity was constrained by k_attach/k_unbind^DP = 22. These three equations give the solution set of the three unknowns. HS, half-site experiment.

^b 95% confidence interval with truncated gaussian model. Lower bound: experimental constraints in ^a; upper bound: one-tailed, α = 5%.

^c In Figs. 2d and 3c, 1/ k_step^ATP = 1/k_max^ATP/HS + 1/k_detach + 1/k_FH,on^ATP[ATP], where 1/ k_FH,on^ATP[ATP] is negligible at high [ATP].