The temperature dependence of kinesin motor-protein mechanochemistry

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

The crowding dynamics of the motor protein kinesin-II

Intraflagellar transport (IFT) in C. elegans chemosensory cilia is an example of functional coordination and cooperation of two motor proteins with distinct motility properties operating together in large groups to transport cargoes: a fast and processive homodimeric kinesin-2, OSM-3, and a slow and less processive heterotrimeric kinesin-2, kinesin-II. To study the mechanism of the collective dynamics of kinesin-II of C. elegans cilia in an in vitro system, we used Total Internal Reflection Fluorescence microscopy to image the motility of truncated, heterodimeric kinesin-II constructs at high motor densities. Using an analysis technique based on correlation of the fluorescence intensities, we extracted quantitative motor parameters, such as motor density, velocity and average run length, from the image. Our experiments and analyses show that kinesin-II motility parameters are far less affected by (self) crowding than OSM-3. Our observations are supported by numerical calculations based on the TASEP-LK model (Totally Asymmetric Simple Exclusion Process-Langmuir Kinetics). From a comparison of data and modelling of OSM-3 and kinesin-II, a general picture emerges of the collective dynamics of the kinesin motors driving IFT in C. elegans chemosensory cilia and the way the motors deal with crowding

Abstracts of National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India. Conference Title: National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020Conference Acronym: RDMPMC-2020Conference Date: 26–27 August 2020Conference Location: Online (Virtual Mode)Conference Organizer: Department of Metallurgical and Materials Engineering, National Institute of Technology JamshedpurCo-organizer: Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, IndiaConference Sponsor: TEQIP-