Table 1.
1: Cardiac myosin actin-activated ATPase and in vitro motility
| βmys | |||||||
|---|---|---|---|---|---|---|---|
| Δ0 NHD | Δ17 @ 20% | Δ17 @ 30% | Δ17 @ 60% | Δ17 MHD | Δ17 HED | ||
| Vmax (s−1) | 1.51±0.08 | 1.59±0.05 | 1.63±0.06 | 2.29±0.24 | 3.09±0.84 | 1.88±0.59 | |
| KM (µM) | 9.33 ± 1.66 | 18.6±1.8 | 37.8±3.5 | 114.4± 20.6 | - | - | |
| sm (µm/s) Qdot | 0.27±0.02 | - | 0.29±0.02 | 0.32±0.03 | 0.40±0.04 | 0.25±0.04 | |
| sm (µm/s) standard | 0.26±0.02 | - | 0.31±0.02 | 0.31±0.01 | - | - | |
| <d> (nm) | 6.0±0.3 | - | 6.2±0.4 | 5.7±0.5 | 6.1±0.5 | 5.5±0.5 | |
| <F> (uf) | 14.4±1.2 | - | 16.8±1.6 | 19.6±2.3 | 24.1±2.0 | 21.7±2.6 | |
| <P> (µm/s) (uf) | 3.9±0.3 | - | 4.4±0.4 | 6.3±0.7 | 9.7±0.5 | 5.5±0.3 | |
| αmys | |||||||
| NTg NHD | WT @ 30% | WT MHD | Δ43 @ 60% | Δ43 MHD | |||
| Vmax (s−1) | 2.67±0.24 | 2.60±0.19 | 2.53±0.44 | 1.50±0.09 | 1.28±0.09 | ||
| KM (µM) | 3.55±1.08 | 3.18±0.80 | - | 4.35±0.85 | - | ||
| sm (µm/s) Qdot | 1.21±0.07 | 1.24±0.06 | 1.31±0.38 | 1.14±0.04 | 1.00±0.14 | ||
| sm (µm/s) standard | 1.02±0.06 | 0.97±0.08 | - | 0.82±0.04 | - | ||
| <d> (nm) | 6.9±0.4 | 6.0±0.3 | 6.0±2.4 | 6.2±0.4 | 6.2±0.4 | ||
| <F> (uf) | 6.6±0.7 | 5.5±0.7 | 4.9±1.4 | 3.8±0.3 | 3.6±0.5 | ||
| <P> (µm/s) (uf) | 8.0±0.9 | 6.8±0.9 | 6.5±2.0 | 4.4±0.4 | 3.7±0.2 | ||
Vmax and KM are defined in eq. S1 from SI. Motility velocity sm from standard and Qdot motility assays occasionally differ for the higher velocity αmys because subtraction of thermal/mechanical fluctuations, possible only with Qdot data, removes some of the lowest velocities in the velocity histogram that are not due to myosin activity. This effect is negligible for βmys. Quantities denoted by <q> are ensemble averages defined in System (ensemble) analytics (Section B. SI) for step-size, d, force F, and power, P. Average force <F> is in arbitrary units of force (uf). All experimental errors indicated are standard deviation. Quantities for the MHD and HED pure species are calculated using eqs. 1 & 7 as explained in Methods with standard deviation estimated by random variate generation from their probability distribution as described (45).