The Robotics, Biomechanics, and Dynamic Systems Laboratory

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Kinesin Intracellular Transport

Motor Protein Locomotion
Mahdi Haghshenas-Jaryani



The video clips on this page show simulations of two different rigid multi-body models for the motor protein Myosin V. The simulations are meant to focus on contact and impact between the protein and actin filament, especially docking. The first model, referred to as the massless protein , is developed using the widely accepted assumption that mass can be neglected at the nanoscale. The second, the massive protein , uses a new approach developed in this laboratory which retains the mass properties. The overall hypothesis is that the massless model gives a more realistic prediction of the motor protein's locomotion. More details are given in the papers on the previous page.


Videos

    by Mahdi Haghshenas-Jaryani     10/14/2011
Massive 3D model of Myosin V with Brownian Motion
This video shows a significant reduction in the effect that the random forces associated with Brownian motion have on the massive 3D model as compared to the massless model or the 2D massive model. This video supports the idea that motor protein locomotion is a combination of deterministic and random components where Brownian motion and diffusion are not the dominant motions.

    by Mahdi Haghshenas-Jaryani     10/14/2011
Massive 3D model of Myosin V Deterministic Stepping
This video shows the motion of the 3D model without random forces. The protein shows similar deterministic behavior as the 2D model. Notice the oscillations at the very beginning and the very end of the video as the heads attempt to dock.

    by Mahdi Haghshenas-Jaryani     10/14/2011
Massive 3D model of Myosin V Deterministic Docking Oscillations
This video highlights the oscillations during docking predicted by the new model we have developed.

    by Mahdi Haghshenas-Jaryani     10/14/2011
Massless 3D model of Myosin V with Brownian Motion
This video shows a step for the 3D massless Myosin V model under the influence of the random forces associated with Brownian motion. Notice the pronounced effect of the random forces which prevent the head from docking. This aligns with ideas about the "Brownian motor" that describe the protein's motion as being dominated by random forces.

    by Mahdi Haghshenas-Jaryani     10/14/2011
Massless 3D model of Myosin V Deterministic Stepping
This video shows a step for the 3D massless Myosin V model. Notice that the head stays in contact with the actin filament throughout most of the step.

Download     by Mahdi Haghshenas     10/19/2009
Massive model of Kinesin with Brownian Motion
A viscous coefficient of friction of 5e8 ag/ms was used which is 5 times that of water. Notice the oscillatory behavior as the head attempts to dock.

Download     by Alan Bowling     4/29/2008
Massless Protein Deterministic Step
This video shows a single step of the massless protein without the effects of the random forces associated with Brownian motion. Notice that the trailing head stays in contact with the actin filament throughout most of the step. At the end of step the protein isn't able to effectively dock with the binding site on the actin filament, so the simulation is stopped after a time.

Download     by Alan Bowling     4/29/2008
Massive Protein Deterministic Step
This video shows a single step of the massive protein without the effects of the random forces associated with Brownian motion. Notice that the trailing head rolls over and leaves the actin filament at the beginning of the step, in contrast to the behavior of the massless protein. The massive protein has no trouble docking at the binding site on the actin filament.

Download     by Alan Bowling     4/29/2008
Massless Protein with Brownian Motion
This video shows the massless protein stepping under the influence of the random forces associated with Brownian motion. It has been suggested that Brownian motion would fix the docking problems for the massless protein, but in this particular case it doesn't. The massless protein is able to dock at the first step, but not on the second, so the simulation is stopped after a time.

Download     by Alan Bowling     4/29/2008
Massive Protein with Brownian Motion
This video shows the massive protein stepping under the influence of the random forces associated with Brownian motion. The massive protein still has no trouble docking in the prescence of random forces. This suggests that the massive protein may be a more realistic model of motor protein behavior, at least for Myosin V.


Links

The Robotics, Biomechanics, and Dynamic Systems Laboratory



last updated October 14, 2011