em2134x
3 HN recommenders · recommended in 8 months, 2018–2023
0:22 · 2.3M views · Aug 17, 2012
A very short animation of a kinesin motor protein walking along a microtubule inside a cell, carrying cargo.
Shared as a vivid illustration of molecular machines at work inside cells.
8 comments from Hacker News
If you think that’s cool you might also like to see the motor proteins that walk along inside our cells. There are a few types including the ones that make muscles work. Kinesin is fun because it has little legs made of proteins. It gloms onto big bubbles of stuff inside the cell and carries them along pathways to their destination. Chemical reactions cause the proteins to fold in the right way to take each step. This shows how they look. this video This explains the mechanisms that they use to walk. [LINK]
> the molecules seem to have intent Take a look at dynein and kinesin walking along microtubules while dragging along their cargo. It's pretty neat. Unknown is how the really simple microtubules get to their destination while building themselves just ahead of the walkers or how the walkers know which turns to take. this video [LINK] this video
Then you have to watch these videos too: [LINK] For example, this looks like a cartoon but it really behaves so (except that the molecules are too small to have the colors, as in other visualizations): this video
Chemicals don't need to chemically react. Especially for biology, merely existing is enough. Lots of biological regulation is done by influencing three-dimensional shapes of the huge highly complex structures called proteins. Organic chemistry especially is a science of complex three dimensional structures and its dynamic changes, at least as important as actually altering the chemical structure. Often they are not static but have moving parts, because not all bonds restrict movement of the atoms connected through that bond in relation to the other part. Many have what's call binding sites - other molecules fitting to those sites won't be altered or alter the chemical structure of the protein. They alter the shape . Proteins are machines, pretty much literally. For example, there are channel proteins, and a molecule docking on a binding site of such a protein might open or close that channel for certain molecules. The variety of those molecular machinery (really, literally) is huge. You can influence machines not just by breaking them down, you can just throw a spanner between their gears. Things that matter are not just shape and size, but also polarity of the parts. Polar components of a molecule influence polar components of proteins if they can get close enough, which influence the shape. Binding sites, as only one example: Description: [LINK] Images: [LINK] Example - 22 second movie - for a protein-machine whose function it is to move stuff around: this video Example for io
Proteins are 1-dimensional chains of 'lego-like' molecules that fold into atomically-precise 3D tools. There are ~20 types of legos that have properties that differ along a number of axis like hydrophobicity, charge, reactivity, size, flexibility, etc. And those 20, in combination, seem to be enough to build all of the tools life needs to interact with its environment. Most proteins are assemblies of a few hundred such 'legos' (again, of which there are 20 types). Those 3D structures then, because they're encoded in the 'tape-like' DNA, can actually themselves be modular, rearranged, and this chunk can be lopped off and plopped onto that chunk, or assembled with this chunk over here. When you string a 'firefly-shine' protein next to a 'in-the-nucleus' protein, the firefly-shine protein will now be physically connected to the 'in-the-nucleus' signal, so you get firefly-shine in the nucleus. Now encode all the things proteins can do: bind to things, enzymatically make things, go places, make structures, sense chemicals, light, force, electricity, other atoms, etc. - and you get little multi-part robots made of those various active 'chunks'. If you have a protein piece that itself assembles in a hexagonal-like shape, you could imagine assembling a number of them into a soccer ball - just as a virus does to protect its DNA. Or if there are small Brownian-aware 'ratchets' attached to stiff fiber-like proteins, you can get proteins that move or walk: this video The microtubule's they'