Transport by a Kinesin in the Presence of Magnetic Nanoparticles

Abstract

Superparamagnetic nanoparticles are used to influence the medium in which kinesin nanotransport occurs. Simulation results show that nanoparticles form chain-like structures aligned with the direction of applied external magnetic field. The strength of the links in these chains depends on the properties of the particles and on the intensity of the applied magnetic field. Therefore, altering the magnetic field can be used to dynamically control the loads kinesins have to overcome - analogous to modifying properties of the medium in which the transport takes place.The components of the motor protein, namely its two heads, two neck linkers and a neck and a cargo linker, are considered to be linear elastic elements. The chemical reaction of ATP/ADP and the heads is modeled using Michaelis-Menten kinetics and the Arrhenius equation. The overall model is shown to successfully capture the hand-over-hand motion of kinesin. By simulating the transport of a cargo by kinesin through obstacles created by the magnetic nanoparticles, it is shown that the resisting force created by chains of magnetic nanoparticles affects the speed of kinesin transport.However, characterizing the motion of a kinesin in the presence of many magnetic nanoparticles requires stochastic simulations at a variety of conditions. The required computational time is prohibitive. Hence, a generalized model is developed to estimate the force on the cargo without solving the full-order system dynamics every time. Finally, the motion of cargo under varying magnetic fields is studied. These results can be used to detect possible deficiencies in kinesin - microtubule interactions.