Table 1 Summary of helical motions and microtubule-activated ATPase activity.

From: CYK4 relaxes the bias in the off-axis motion by MKLP1 kinesin-6

Construct

Suspended microtubule

Non-suspended microtubule

Microtubule activated ATPase

 

Pitch (µm)

Longitudinal velocity (µm s−1)

Rotational velocity (rev s−1)

Longitudinal velocity (µm s−1)

kcat (s−1 head−1)

KM (µM)

M2

0.8 ± 0.1 (n = 36)

0.30 ± 0.03 (n = 36)

0.37 ± 0.08 (n = 36)

0.21 ± 0.04 (n = 12)

39 ± 1

0.4 ± 0.04

M2C2

1.5 ± 0.8 (n = 47)

0.19 ± 0.05 (n = 47)

0.12 ± 0.05 (n = 47)

0.15 ± 0.05 (n = 10)

45 ± 1

1.6 ± 0.1

M1

2.1 ± 1.6 (n = 47)

0.24 ± 0.04 (n = 47)

0.11 ± 0.09 (n = 47)

N.E.

37 ± 4

7.1 ± 1.4

  1. In assays using either dimeric M2, centralspindlin complex M2C2 or monomeric M1 coated-beads, only beads that moved more than ~ 1 µm were analyzed. The positive values in rotational velocity indicate that the helical motion is left-handed. Data are given as mean ± SD. n, number of beads. In the ATPase assays, the microtubule-stimulated ATPase activities were measured from three independent experiments under the same conditions. The turn-over rate (kcat) and Michaelis constant for microtubules (KM) were obtained from best fit by the Michaelis-Menten equation.
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