TABLE 1.
Summary of Sc-MyoII and Sc-MyoV ATPase and motility activities with muscle and yeast actins
|
Sc-MyoII (Myo1p) |
Sc-MyoV (Myo2p) |
|||||||
|---|---|---|---|---|---|---|---|---|
| VMAXa | Kma | Catalytic efficiencyb | Motility ratec | VMAXa | Kma | Catalytic efficiencyb | Motility ratec | |
| s−1 | μm | μm/s | s−1 | μm | μm/s | |||
| Muscle actin | 1.8 ± 0.1 | 11.1 ± 1.5 | 0.17 | 0.87 ± 0.17d (40) | 21.5 ± 0.5 | 6.8 ± 0.6 | 3.17 | 1.51 ± 0.34 (40) |
| Wild-type yeast actin | 3.2 ± 0.2 | 9.6 ± 2.2 | 0.34 | 1.17 ± 0.28 (150) | 39.9 ± 2.6 | 16.1 ± 2.6 | 2.47 | 1.33 ± 0.30 (40) |
| 4Ac yeast actin | 0.93 ± 0.20d (123) | 1.60 ± 0.33 (20) | ||||||
| Sub12 yeast actin | 0.86 ± 0.29d (109) | 1.20 ± 0.27 (20) | ||||||
a VMAX and Km (±S.E.) calculated by fitting actin-activated ATPase data (from Figs. 3A and 4A) to the Michaelis-Menten equation. ATPase activity: molecules of ATP hydrolyzed per motor per second.
b Catalytic efficiency, VMAX/Km.
c Mean in vitro motility rate ± S.D. (n is indicated in parentheses).
d p < 0.001 when compared to yeast actin.