Flexural Stiffness of Myosin Va Subdomains as Measured from Tethered Particle Motion

Table 1

Calculated tethered motions and mechanical properties of MyoVa subdomains. The tethered motions and mechanical properties ± propagated standard errors are derived from image size parameters for the tethered Qdot () and reference Qdot () (see Section 2). The numbers of measured particles in the tethered () and reference states () for each domain are presented. The tether lengths () are those presented in Figure 2. Persistence length is given for the S1 subdomain but is not applicable for more complex geometries.

Subdomain			Tether length, (nm)	Motion versus reference, (nm)	Motion versus Actin, (nm)	Flexural stiffness,; (pN/nm)	Persistence; length, (nm)
Actin	888	69	NA	17.38 ± 5.56	NA	NA	NA
S1	393	66	44	20.47 ± 15.80	10.82 ± 5.92	0.0346 ± 0.0379	242 ± 109
S1 + Ca	98	9	44	22.69 ± 19.94	13.92 ± 22.25	0.0209 ± 0.0669	146 ± 99
HMM	361	57	67	28.94 ± 11.35	23.14 ± 3.61	0.00758 ± 0.00236	NA
FL	327	69	92	31.01 ± 9.27	25.69 ± 5.24	0.00615 ± 0.00251	NA
Distal rod	NA	NA		NA	11.15 ± 4.82	0.0326 ± 0.00282

Distal rod deflection was calculated from FL relative to HMM rather than Actin.