Table 4.

Filament mechanical flexibility properties

Uncertainties are S.D. from fitting.

	Filament bending persistence length Lpa	Intersubunit torsional rigidity Csubb	Intersubunit torsional constant αc
	μm	newtons m2 radians−1	newtons m2 radians−1
Bare	8.3 ± 0.4	1.09 ± 0.07 × 10−27	3.95 ± 0.26 × 10−19
WT	2.6 ± 0.3	0.21 ± 0.05 × 10−27	0.75 ± 0.02 × 10−19
S3D	6.3 ± 1.2	1.26 ± 0.17 × 10−27	4.60 ± 0.63 × 10−19

^a From cosine correlation analysis of filaments (Eq. 6).

^b Calculated from C_sub = αh, assuming a subunit height (h) of 2.75 nm (12).

^c From model-dependent analysis of phosphorescence anisotropy decay in Fig. 5 (12).