What are prions and why are they so hard to kill ?


What are prions and why are they so hard to kill ?

In: Biology

Prions are wrongly folded proteins. They multiply by folding other neighbouring proteins wrongly too. (And that makes you sick because those proteins won’t do their job anymore)

You can kill (or better destroy, they don’t live) them easily. But you can’t easily distinguish them from normal proteins, so destroying prions without hurting other proteins is very hard.

Prions are incorrectly folded proteins which don’t work as needed and also make other proteins re-fold incorrectly.

Proteins are long chain molecules (consisting of amino-acids) which fold automatically into a certain shape defined by precisely which amino-acids sit precisely where along the chain. The shape they fold into makes them superb catalyzers of various specific chemical reactions, because this shape kinda has “slots” in it where other respectively shaped molecules fit. These chemical reactions are basically what life is, so it’s pretty important that proteins fold into correct shapes. Otherwise they won’t work and there won’t be some chemical reaction which might be necessary for life. So sometimes proteins do fold incorrectly, and the freakish thing is that sometimes these incorrectly folded proteins make other proteins of the same kind reshape themselves in the same incorrect way. So when such prions appear in the body, they spread throughout it and eventually turn every protein of a certain kind into themselves. This essentially stops the relevant chemical reaction altogether and thus kills the organism.

(this could be wrong, my knowledge of this is pretty puddle deep)
Prions are proteins, but due to their shapes they cause other proteins that they touch to fold. This folding makes the protein unusable (or very inefficient). This prion then floats in the body rendering proteins it touches unusable. Because prions are just proteins they can’t be ‘killed’ but they can be destroyed through things like extreme heat.
However this isn’t practical as destroying the prion would also damage the healthy proteins.
There’s not too much consensus on how they are created but the leading theory is that certain elements (like aluminium) interacts with healthy proteins and folds them turning into prions.
Prions can be anywhere in the body, but mostly accumulate in the brain (not sure why)
If I’ve made a mistake comment below 🙂

Prions are protons which are folded wrong and which will cause other similar proteins to also get folded the same way. This can happen spontaniously but this is extremely rare. However the most likely source of prion diseases is from others who are infected. There are a lot of proteins which are shared between different creatures, at least close enough. So a number of prion diseases can spread between different animal species. When a prion disease does infect someone it does not usually cause harm by itself but it does prevent the protein from doing its intended job which can be deadly. The problem with prions is that it is not actually anything foreign as the proteins that cause the disease are made by your own cells according to your own genes. A lot of the immune systems defenses are aimed at preventing foreign intruders but prions are not foreign in the same way. So the immune system will not act on prions.

Prions are altered proteins, you can’t really kill them because they’re not like a virus or bacteria.
These proteins are often infectious and can create more prions from “normal” proteins (imagine a zombie kind of situation).

We still don’t know why they are so hard to “kill”, some scientists say that it’s because all our methods target DNA and/or RNA, and they don’t have those.
What we know is that they resist digestion, really high temperatures (that you can’t subject a person to) and even ionising radiation. They also stick to medical equipment and to get rid of them you have to sterilise them heavily with bleach and heat (and that doesn’t always work, it’s better to just throw the instruments out).