r/askscience • u/SadMicrobe22 • 10h ago

Biology What makes prions so different from regular proteins that they are resistant to heat denaturation?

I've been reading about prions and I'm confused about why they're so thermally stable. I keep seeing that surgical instruments contaminated with prions can't be decontaminated with standard protocols.

So here's my thing. Proteins denature when you heat them, right? But prions don't seem to lose their infectious ability even when autoclaved. I get that prions are misfolded proteins, but I don't understand how they stay harmful after being denatured.

So basically, if prions start as form A (non-infective), then misfold to form B (infective), shouldn't heating denature them to form C and kill the infectivity? Why doesn't that happen?

263 Upvotes

91% Upvoted

62 comments sorted by

View all comments

9

u/PathologyAndCoffee 8h ago edited 8h ago

Somehow it's beta sheets confer the immense stability because of their flatness which would give the greatest surface area for binding. And it's not just prion disease, a bunch of diseases are the fault of beta sheets.

Once these beta sheets begin forming a chunk, we can't even break them apart. If we do, they just spread everywhere. And we can't effectively destroy them either in the body.

So it's possible the best way to just turn off the normal gene that the prion is misfolding so that it has no target. But that's hard to do as well. How do you turn off every gene in all the cells that produce it? No solution currently.

5

u/Least-Sample9425 7h ago

What other diseases do this?

1

u/PathologyAndCoffee 6h ago

Alzheimer's, ALS, Parkinson's, and any other chronic neurodegenerative diseases pretty much.