After viewing the animations that Martin posted, it came to my attention that in most of them, there seems to be, perhaps, I agree that there's certainly room for misunderstanding when it comes to analogies etc used for illustrating scientific concepts, and I noticed there seems to be prevalent misunderstanding about the mechanism of kinesin "walking".
Those of you who took BIPH2000 last year would remember that one of the topics covered was in fact the Kinesin motor protein. Due to the cellular environment, there is no specific "swinging" of the lagging globular motor head forward, as the complex progress along the microtubule substrate, as is show in countless YouTube animations. Kinesin's Reynold's number would be indicative of this.
While it is helpful to think of Kinesin transporting its load down a microtubule by "walking" like a packhorse that it effectively is, it definitely seems make room for misunderstanding. It would probably all be much clearer to the viewer if the binding and hydrolysis of ATP, and release of ADP from the globular motor heads were able to be depicted.
Below illustrates my point, and also is a great example of why one should really avoid wikipedia for correct information:
While cute, it's incorrect.
The video "Fantastic Vesicle Traffic" is interesting, but again somewhat incorrect.
A video of the motor protein in vitro illustrates that the movement is somewhat more of a random phenomenon, as opposed to the structured periodic steps taken in the other animation. One can never go wrong with observing the real thing: http://www.youtube.com/watch?v=4sEyUBoWBt4&feature=related
Again, I could just be being nit-picky.
Divine.
Those of you who took BIPH2000 last year would remember that one of the topics covered was in fact the Kinesin motor protein. Due to the cellular environment, there is no specific "swinging" of the lagging globular motor head forward, as the complex progress along the microtubule substrate, as is show in countless YouTube animations. Kinesin's Reynold's number would be indicative of this.
While it is helpful to think of Kinesin transporting its load down a microtubule by "walking" like a packhorse that it effectively is, it definitely seems make room for misunderstanding. It would probably all be much clearer to the viewer if the binding and hydrolysis of ATP, and release of ADP from the globular motor heads were able to be depicted.
Below illustrates my point, and also is a great example of why one should really avoid wikipedia for correct information:
The video "Fantastic Vesicle Traffic" is interesting, but again somewhat incorrect.
A video of the motor protein in vitro illustrates that the movement is somewhat more of a random phenomenon, as opposed to the structured periodic steps taken in the other animation. One can never go wrong with observing the real thing: http://www.youtube.com/watch?v=4sEyUBoWBt4&feature=related
Again, I could just be being nit-picky.
Divine.
Remember one of the interesting lessons from 2-headed kinesin is that the appearance of the power stroke within the cycle is different than in macroscopic engines. The energy of hydrolosyis of ATP is not converted directly into motion; rather it serves only to introduce an irreversible step into the cycle, allowing the definition of a 'forward direction'. -Seth
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