The temperature dependence of kinesin motor-protein mechanochemistry

https://doi.org/10.1016/j.bbrc.2020.06.004Get rights and content
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Highlights

  • We measured the temperature dependence of single-molecule velocity and run length of three kinesin motor proteins.

  • Velocity and run length of all three motors showed a non-Arrhenius temperature dependence.

  • The data can be described with a two-state kinetic model of the motors’ mechanochemistry.

Abstract

Biophysical studies of the mechanochemical cycle of kinesin motors are essential for understanding the mechanism of energy conversion. Here, we report a systematic study of the impact of temperature on velocity and run length of homodimeric Drosophila kinesin-1, homodimeric C. elegans OSM-3 and heterodimeric C. elegans kinesin-II motor proteins using in vitro single-molecule motility assays. Under saturated ATP conditions, kinesin-1 and OSM-3 are fast and processive motors compared to kinesin-II. From in vitro motility assays employing single-molecule fluorescence microscopy, we extracted single-motor velocities and run lengths in a temperature range from 15 °C to 35 °C. Both parameters showed a non-Arrhenius temperature dependence for all three motors, which could be quantitatively modeled using a simplified, two-state kinetic model of the mechanochemistry of the three motors, providing new insights in the temperature dependence of their mechanochemistry.

Keywords

Microtubules
Motor proteins
Kinesins
Caenorhabditis elegans
TIRF microscopy
Single-molecule fluorescence microscopy
Single molecule analysis
Temperature
ATP hydrolysis cycle

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