Table 3.
Hydrodynamic analysis of full-length Myo1c
|
Property |
Temperature |
Full-length Myo1c 100 μM EGTA |
Full-length Myo1c 25 μM CaCl2 |
| Sedimentation coefficient | 4°C 25°C |
6.70 ± 0.07 S (n = 5) | 6.90 ± 0.08 S (n = 4) |
| 6.28 ± 0.21 S (n = 8) | * | ||
| Stokes radius | 4°C 25°C |
6.06 ± 0.08 nm (n = 7) | 6.07 ± 0.05 nm (n = 4) |
| 5.78 ± 0.11 nm (n = 5) | * | ||
| Molecular mass | 4°C 25°C |
168 ± 4 kD | 4°C: 173 ± 3 kD |
| 150 ± 7 kD | ND | ||
| Frictional ratio | 4°C 25°C |
1.7 ± 0.1 | 1.7 ± 0.1 |
| 1.7 ± 0.1 | ND | ||
| Calmodulins per molecule | 4°C 25°C |
2.5 ± 0.2 | 2.9 ± 0.2 |
| 1.5 ± 0.4 | ND |
* Very low levels of protein detected.
Full-length Myo1c was co-expressed with calmodulin, purified, and subjected to sucrose-gradient centrifugation or gel-filtration analysis. Myo1c was detected by ELISA (sucrose gradients) or by absorption at 280 nm (gel filtration). Molecular mass was determined using the Stokes-Einstein equation; the number of calmodulins was estimated by subtracting the mass of the Myo1c heavy chain from the estimated molecular mass, then dividing the remainder by the mass of calmodulin (16.7 kD). Values reported are mean ± standard deviation. ND, not determined.