Table 1.

Fixed and free parameters and defined variables used in models

Fixed parameters
Symbol	Description	Value	Units	Reference
a	Average radius of fibers	20.6 ± 4.3	μm	Fig. 2 legend
Mo	Oligomeric molecular weight of proteina	11.9–340.3	kDa	Table 2
Dw	Diffusion in dilute aqueous solution of proteina	(2.48–7.75) × 10−7	cm2 s−1	Table 2
Rh	Hydrodynamic radius of proteina	1.83–5.69	nm	Table 2
Vh	Hydrodynamic volume of proteina	0.0129–0.0137	dL/g	Interpolated from (22)
Rthin	Radius of thin filament	4	nm	(66)
Rthick	Radius of thick filament	6.5	nm	(66)
Ro	Average radius of thick and thin filaments	5.25	nm	(66)
L	Half center-to-center thick-thin filament spacing	12.85	nm	(15)
ns	Supramolecular binding cooperativity exponentb	5c	unitless	—
k	Boltzmann constant	1.381 × 10−23	J K−1
η	Viscosity of water at 7°C, at 39.4°C	1.45, 0.65	cP	(37)
T	Temperature of experimental conditions	280, 312.4	K
Free parameters
Symbol	Description	Optimization ranged	Optimum Values	Units
φ	Ease of vacancy, hydrodynamic volume product	0.01–1.00	0.12 ± 0.01	dL g−1
kb	Apparent binding constant of proteins to lattice	0–15	0.96 ± 0.17	unitless
ksmax	Maximal supramolecular complex binding constant	10–1500	628 ± 111	unitless
ρ50	Total cytosolic protein density at 50% binding	0–50	21.96 ± 0.90	mmol L−1
D	Optimized diffusion coefficient (Constant D)	(0–1.00) × 10−7	(0.08–0.68) × 10−7	cm2 s−1
Variables
Symbol	Description	Returned value rangee		Units
ρ(r,t)	Total cytosolic protein density in a radial annulus	0–1.121		mmol L−1
D(r,t)	Variable diffusion coefficient (Variable D)f	0.20–1.60 × 10−7		cm2 s−1

^aValues depend on protein species.

^bIndex of the steepness of the transition from maximal to minimal supramolecular binding, defined in Eq. 6.

^cFor the simulations, the value was fixed at 5, corresponding to an arbitrarily high value for cooperativity of the supramolecular binding and dissociation (see text for details).

^dRange of values over which optimum value is determined.

^eRange of values returned from simulations. The values tabulated here for the optimized parameters are the mean ± SD over the 20 best fits to the data. The RMS error between simulation and data of the 20 best fits is 1.66 ± 0.02%.

^fEvaluated at t/a² = 0.035.