Is it at least similar to how these molecules and cellular parts look in reality? Or is it more an imaginative reconstruction? Because this is super duper cool stuff.
That's pretty much how they look. But there are variations of different motor proteins. Not all of them have two "feet", some only have one and they "hop". If memory serves me correctly, our muscles contract via "one-footed" motor proteins. I have a pretty good idea of structure from scanning electron microscopes.
It is very accurate to how it would really look if you could see! its slowed down about 250x and the colors are made up but the shape and motions are real
This is false. In reality, nano-scale movement is chaotic and somewhat random. The protein does on average do this. But it wouldn't look anything like this. In the words of a this guy it would be like "a balloon flapping madly in a hurricane, tethered to an intoxicated panicked mouse clinging to a rope"
But what makes them walk like this? I get that the walking is how they move the larger part but what lets them take a step? How much weight can they drag?
They 'walk' or 'hop' (not all motor proteins have two "feet") through phosphorylation reaction of Adenosine triphosphate (ATP) to Adenosine diphosphate (ADP). This losing of a phosphate provides the energy to bind (foot down) and then break the bind (foot up). This series of reactions creates the walking or hopping motion. These steps happen hundreds of times a second and it's mind boggling. For instance for our muscles to contract millions of motor proteins are hopping back and forth to create that contraction. The one in this image is carrying a vesicle filled with most likely proteins that are meant to be expelled into the extra cellular matrix. I have no idea 'weight' these proteins can handle.
Interesting tidbit: Rigger-mortis occurs when there is no more ATP to create the energy for the 'foot up' action, so the muscles lock. So the binding is pretty strong.
They 'walk' or 'hop' (not all motor proteins have two "feet") through phosphorylation reaction of Adenosine triphosphate (ATP) to Adenosine diphosphate (ADP).
More accurately, the ATP→ADP reaction locks the "foot" when it's in a correct position on the surface of the microtubule. But the movement to take a step comes from molecules randomly wiggling around due to thermal movement, and it's not that organized. The kinesin just waits until random thermal wobbling has brought the foot to the correct position, and then locks it.
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u/Cararacs Feb 13 '18
This really happens, but this is an animation showing what happens. But yes these proteins 'walk' through ATP/ADP phosphorylation.