Table 1.
Rates of depolymerization of GDP and GMPCPP microtubules and radius of curvature of oligomers
| Conditions | GDP microtubules
|
GMPCPP microtubules
|
||
|---|---|---|---|---|
| Rate, μm/min | Radius, nm | Rate, μm/min | Radius, nm | |
| Cooling | −20.3 ± 4.9 (8, 163) | 19.0 ± 4.1 (140) | −0.3 ± 0.1 (8, 274) | ND |
| 4 mM Ca2+ | −611 ± 125 (7, 90) | 20.0 ± 4.1 (163) | −13.0 ± 3.2 (12, 176) | 38.6 ± 7.1 (160) |
| 40 mM Ca2+ | ND | 21.1 ± 4.3 (123) | −72.0 ± 45.0 (3, 60) | 36.2 ± 10.1 (108) |
The rates of depolymerization were measured on individual microtubules using video-DIC light microscopy. The two numbers in parentheses indicate the number of microtubules analyzed and the number of rate measurements performed. The radii of curvature were measured on oligomers present at the ends of shrinking microtubules or in the background of the cryo-EM images. The number in parentheses indicates the number of measurements performed. Mean values are given ± their standard deviation. ND, not determined.