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Processivity of kinesin motility is enhanced on increasing temperature

View Article: PubMed Central - PubMed

ABSTRACT

Kinesin is a motor protein that processively moves step by step along a microtubule. To investigate the effects of temperature on run length, i.e., processivity of kinesin motility, we performed a single-molecular bead assay at temperature range of 20–40°C. An increase in the walking velocity of kinesin corresponded to the Arrhenius activation enthalpy of 48 kJ/mol, being consistent with the previous reports. Here, we found that the run length increased, that is, the kinesin processivity enhanced with increasing temperature. Then, we estimated the probability of detachment of kinesin from a microtubule per one 8-nm stepping event, and found that it diminishes from 0.014 to 0.006/step with increasing temperature from 20 to 40°C. And we noticed that prolonged incubation at 30, 35 and 40°C significantly slowed down the walking velocity, but further increased the run length and duration. Those results are interpreted according to the effect of temperature on the rate constants of some key kinetic steps in the ATPase cycle.

No MeSH data available.


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Temperature dependence of run length. The data at 20°C (A) and 25°C (B) were obtained between 1 and 11 min after the incubation at each temperature. On the other hand, for 30°C (C), 35°C (D) and 40°C (E), the data obtained between 1 and 6 min of incubation are shown by open bars, whereas those obtained between 6 and 11 min of incubation are shown by gray bars, because they showed a different set of values although the shape of the distribution was the same, i.e., approximated by a single exponential. Distribution of run lengths was fitted by an exponential function (a solid or a dashed curve). Here, the run lengths shorter than 0.5 μm were excluded from the analysis. The average run length, which was defined as the characteristic run length of the exponential function, obtained from each distribution shown here, was 0.56, 0.66, 0.93 (0.94), 1.07 (1.51) and 1.28 (1.65) μm at 20, 25, 30, 35 and 40°C, respectively (the values in the parentheses, the data for 6–11 min). In Fig. 2F, these values are shown by closed circles for 20 and 25°C and left-half filled circles for 30, 35 and 40°C connected by a solid line. Right-half filled circles (connected by a dashed line) show the average run length obtained from the data taken between 6 and 11 min of incubation at 30, 35 and 40°C.
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f2-2_13: Temperature dependence of run length. The data at 20°C (A) and 25°C (B) were obtained between 1 and 11 min after the incubation at each temperature. On the other hand, for 30°C (C), 35°C (D) and 40°C (E), the data obtained between 1 and 6 min of incubation are shown by open bars, whereas those obtained between 6 and 11 min of incubation are shown by gray bars, because they showed a different set of values although the shape of the distribution was the same, i.e., approximated by a single exponential. Distribution of run lengths was fitted by an exponential function (a solid or a dashed curve). Here, the run lengths shorter than 0.5 μm were excluded from the analysis. The average run length, which was defined as the characteristic run length of the exponential function, obtained from each distribution shown here, was 0.56, 0.66, 0.93 (0.94), 1.07 (1.51) and 1.28 (1.65) μm at 20, 25, 30, 35 and 40°C, respectively (the values in the parentheses, the data for 6–11 min). In Fig. 2F, these values are shown by closed circles for 20 and 25°C and left-half filled circles for 30, 35 and 40°C connected by a solid line. Right-half filled circles (connected by a dashed line) show the average run length obtained from the data taken between 6 and 11 min of incubation at 30, 35 and 40°C.

Mentions: Figure 2 shows the distribution of run length at each temperature, which could be fitted by a single-exponential function, being consistent with the previous results15,25. As the temperature increased, the average run length became longer, and eventually increased more than twice from 0.6 μm to 1.3 μm with increasing temperature from 20 to 40°C. The results are summarized in Fig. 2F (points connected by a solid line). The fact that the run length increases at higher temperature was briefly mentioned in our previous paper16. Similar results were also reported for ncd and Eg5 molecular motors4.


Processivity of kinesin motility is enhanced on increasing temperature
Temperature dependence of run length. The data at 20°C (A) and 25°C (B) were obtained between 1 and 11 min after the incubation at each temperature. On the other hand, for 30°C (C), 35°C (D) and 40°C (E), the data obtained between 1 and 6 min of incubation are shown by open bars, whereas those obtained between 6 and 11 min of incubation are shown by gray bars, because they showed a different set of values although the shape of the distribution was the same, i.e., approximated by a single exponential. Distribution of run lengths was fitted by an exponential function (a solid or a dashed curve). Here, the run lengths shorter than 0.5 μm were excluded from the analysis. The average run length, which was defined as the characteristic run length of the exponential function, obtained from each distribution shown here, was 0.56, 0.66, 0.93 (0.94), 1.07 (1.51) and 1.28 (1.65) μm at 20, 25, 30, 35 and 40°C, respectively (the values in the parentheses, the data for 6–11 min). In Fig. 2F, these values are shown by closed circles for 20 and 25°C and left-half filled circles for 30, 35 and 40°C connected by a solid line. Right-half filled circles (connected by a dashed line) show the average run length obtained from the data taken between 6 and 11 min of incubation at 30, 35 and 40°C.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036643&req=5

f2-2_13: Temperature dependence of run length. The data at 20°C (A) and 25°C (B) were obtained between 1 and 11 min after the incubation at each temperature. On the other hand, for 30°C (C), 35°C (D) and 40°C (E), the data obtained between 1 and 6 min of incubation are shown by open bars, whereas those obtained between 6 and 11 min of incubation are shown by gray bars, because they showed a different set of values although the shape of the distribution was the same, i.e., approximated by a single exponential. Distribution of run lengths was fitted by an exponential function (a solid or a dashed curve). Here, the run lengths shorter than 0.5 μm were excluded from the analysis. The average run length, which was defined as the characteristic run length of the exponential function, obtained from each distribution shown here, was 0.56, 0.66, 0.93 (0.94), 1.07 (1.51) and 1.28 (1.65) μm at 20, 25, 30, 35 and 40°C, respectively (the values in the parentheses, the data for 6–11 min). In Fig. 2F, these values are shown by closed circles for 20 and 25°C and left-half filled circles for 30, 35 and 40°C connected by a solid line. Right-half filled circles (connected by a dashed line) show the average run length obtained from the data taken between 6 and 11 min of incubation at 30, 35 and 40°C.
Mentions: Figure 2 shows the distribution of run length at each temperature, which could be fitted by a single-exponential function, being consistent with the previous results15,25. As the temperature increased, the average run length became longer, and eventually increased more than twice from 0.6 μm to 1.3 μm with increasing temperature from 20 to 40°C. The results are summarized in Fig. 2F (points connected by a solid line). The fact that the run length increases at higher temperature was briefly mentioned in our previous paper16. Similar results were also reported for ncd and Eg5 molecular motors4.

View Article: PubMed Central - PubMed

ABSTRACT

Kinesin is a motor protein that processively moves step by step along a microtubule. To investigate the effects of temperature on run length, i.e., processivity of kinesin motility, we performed a single-molecular bead assay at temperature range of 20–40°C. An increase in the walking velocity of kinesin corresponded to the Arrhenius activation enthalpy of 48 kJ/mol, being consistent with the previous reports. Here, we found that the run length increased, that is, the kinesin processivity enhanced with increasing temperature. Then, we estimated the probability of detachment of kinesin from a microtubule per one 8-nm stepping event, and found that it diminishes from 0.014 to 0.006/step with increasing temperature from 20 to 40°C. And we noticed that prolonged incubation at 30, 35 and 40°C significantly slowed down the walking velocity, but further increased the run length and duration. Those results are interpreted according to the effect of temperature on the rate constants of some key kinetic steps in the ATPase cycle.

No MeSH data available.


Related in: MedlinePlus