Experimental and theoretical investigation of mechanism of Kinesin motility

Abstract

Kinesin is a motor protein capable of utilizing chemical energy from ATP hydrolysis to generate mechanical force to power its progressive motility along a microtubule track. The mechanism of motility has been a subject of extensive study for last decade. Recently, it has been proposed that novel element-cover strand-is essential in power-stroke-like force generation. In this work we attempt an experimental verification of this hypothesis by studying the mechanical properties, such as unloaded velocity, force velocity relationship, stall forces, processivity and step size of kinesin and mutants targeting cover strand region. We show that A9G and D11G mutants move slower and have lower stall force then the wild type molecule, but the mutants are ultraprocessive, make steps of 7nm and have a higher probability of taking backward steps suggesting that, indeed, force generating mechanism might been adversely affected by this mutation but it could also affect flexibility and directionality of the molecule.