Protein Friction Limits Diffusive and Directed Movements of Kinesin Motors on Microtubules

• DOI: 10.1126/science.1174923
• Publication Date: 2009-08-13T21:49:17Z
• Authors: Volker Bormuth; Vladimir Varga; Jonathon Howard; Erik Schäffer
• Keywords: Kinesin; Molecular motor

Friction limits the operation of macroscopic engines and is critical to performance micromechanical devices. We report measurements friction in a biological nanomachine. Using optical tweezers, we characterized frictional drag force individual kinesin-8 motor proteins interacting with their microtubule tracks. At low speeds no energy source, was related diffusion coefficient by Einstein relation. higher speeds, increased nonlinearly, consistent jumping 8 nanometers between adjacent tubulin dimers along microtubule, asymmetric, reflecting structural polarity microtubule. argue that these forces arise from breaking bonds domains they limit speed efficiency kinesin.