There’s a type of disease that infects a person’s brain, is incredibly hard to detect, can kill
extremely quickly, and has no known cure. Hi, I’m Lizah, and this is MinuteYIKES.
These deadly, incurable diseases all start with proteins. Proteins are really long
chains of smaller molecules called amino acids. Through intricate molecular origami, these chains
get folded into complex 3d shapes that enable them to do all sorts of jobs in living things,
like transporting oxygen throughout our bodies. But on occasion, the origami goes awry and a
protein gets folded up wrong. Generally, the body just clears the misfolded protein away.
But not in the case of one specific protein in the brain. For reasons we don’t totally understand,
if one of these proteins misfolds, it persists and goes rogue: whenever it comes across
another protein of its type, it will re-fold that normally-functioning protein into the same shape
as itself, starting a massive chain reaction. Not only can these misfolded proteins no longer
do their job, they also start stacking up into massive clumps within nerve cells,
which block the nerves from sending out signals. Without these crucial signals,
all sorts of body processes go haywire, causing everything from memory loss to organ failure.
This disease, called “Creutzfeldt-Jacobs disease” inevitably leads to death,
often in a matter of just weeks or months. These rogue proteins are called “prions” – short
for “protein infections”. Prions can get into a person’s brain in a few ways. Most of the time,
it happens by sheer chance – a random case of molecular origami going awry. But the
misfolding can also – very rarely – be encoded in a person’s DNA. You can’t “catch” prions like
other contagious diseases… unless you actually eat infected meat. And that can indeed happen,
normally with cows infected with “mad cow disease,” which is the bovine form
of Creutzfeldt-Jacobs disease. Sheep can also get it – then it’s called scrapie – and in deer,
it’s chronic wasting disease. In each of these diseases, the same brain protein is the culprit,
but it’s misfolded in a slightly different way. And it’s the misfolding that makes prion diseases
so tricky. After all, prions are molecularly identical to proteins that normally exist in
our body – they’re just folded differently – so it’s hard to even detect prions in the first
place. And to treat this disease, we'd need a way to go in and either destroy or re-fold all those
misfolded proteins… and that's technology that scientists haven’t figured out yet.
But don’t freak out, Creutzfeldt-Jacobs disease is extremely rare; It’s just as common as being
struck by lightning. And, actually, scientists have recently discovered that prions aren’t all
bad. For example, when a particular protein in a yeast cell misfolds, it makes the cell
wall stronger, which helps the cell survive harsh conditions – and that misfolding can be
passed along to other yeast cells. So while the chain reaction triggered by a simple misfolding
is really dangerous in some circumstances, it can be a life-saver in others. But since prions are
so hard to detect and so poorly understood, we need to keep working to unfold their mysteries.
While we’re still far from understanding prions, we’ve made huge strides in studying proteins in
general thanks in part to DeepMind, this video’s sponsor and a leading AI research lab working on
some of the hardest problems in science. Until recently, researchers were only able to study
the 3D structure of only a fraction of the millions of known proteins. But using AI,
DeepMind’s AlphaFold system is able to predict a protein’s structure solely
based on its amino acid sequence, providing deeper insights into how a protein works and
what it does. In partnership with EMBL’s European Bioinformatics Institute, they’ve released a free
database with the predicted structures of nearly all cataloged proteins. In just eighteen months,
AlphaFold has been accessed by nearly a million researchers and has helped accelerate
progress on problems ranging from plastic pollution to antibiotic resistance. Check
it out yourself – and marvel at the beautiful proteins – at https://alphafold.ebi.ac.uk/