. Author manuscript; available in PMC: 2012 Dec 16.

Published in final edited form as: J Mol Biol. 2011 Oct 20;414(5):667–680. doi: 10.1016/j.jmb.2011.10.026

Table 1.

Velocity and force, measured by in vitro motility assays

	+Ca²⁺ (activating solution, pCa 4.73)		−Ca²⁺ (relaxing solution)

	Velocity μm/s	Force pN/μm	Velocity μm/s	Force pN/μm

−Tm	4.68±0.09 (15)^**	1.07±0.06 (38)^**
Δ2Tm	5.71±0.09 (29)^**	0.48±0.04 (58)^**	0.26±0.05 (4)	0
Δ3Tm	4.90±0.29 (9)^**	0.37±0.03 (74)^**	0.36±0.03 (10)	0
Δ6Tm	6.26±0.13 (22)^**	1.52±0.16 (48)	6.47±0.12 (9)^**	0.66±0.05 (47)^**
wtTm	7.70±0.07 (16)	1.63±0.06 (101)	0.33±0.02 (10)	0
P2sTm	6.73±0.19 (10)^**	1.46±0.08 (55)^(*)	0.32±0.02 (10)	0
P3sTm	6.92±0.14 (12)^**	1.53±0.09 (56)	0.39±0.02 (10)	0
P2P3sTm	9.27±0.18 (11)^**	2.11±0.12 (85)^**	0.33±0.02 (10)	0
P1P5Tm	6.92±0.23 (18)^**	2.06±0.12 (66)^**	5.41±0.22 (8)^**	0.28±0.03 (32)^**

For velocity measurements, velocity distribution such as shown in Fig. 1 was deduced from a video record consisting of 3 sec, and then the distribution was fitted to Eq. 1 to find V_c. V_c was then averaged for many records, and shown with ±SEM in this Table. For force measurements, the filament-attached beads are trapped by optical tweezers, the thin filaments and HMM interaction was performed, then force was measured (Fig. 2), histogram (Fig. 3) was created, and averaged. 0: force was not detectable. Experiments were performed in the presence of 2 mM MgATP at 24°C. In comparison, the velocity measured in the rigor solution (no ATP, no Ca) was 0.40±0.01 (N=6) for wtTm, and 0.45±0.04 (N=4) in the absence of Tm and Tn; Force was not detectable.

^**

P≤0.01,

0.01<P≤0.05, and

^(*)

0.05<P≤0.1 compared to wtTm (based on paired T-tests).