Prions are infectious protein particles that can cause diseases by changing the structure of normal proteins in the body. Unlike bacteria or viruses, prions do not contain DNA or RNA — they are made only of protein.
1. Nature of Prions:
- Prions are abnormally folded versions of a normal protein called PrP (prion protein) found in the brain and nervous system.
- The normal form (PrPᶜ) has a safe, healthy structure.
- The prion form (PrPˢᶜ) is misfolded and has an abnormal, rigid shape.
2. How Prions Affect Protein Function:
- When prion proteins enter the body, they induce normal proteins to fold incorrectly into the prion shape.
- These misfolded proteins lose their normal function and start clumping together in the brain.
- The clumps damage nerve cells, leading to holes in brain tissue and severe neurological symptoms.
3. Diseases Caused by Prions:
Prion diseases are rare but always fatal. Examples include:
- Creutzfeldt-Jakob disease (CJD) in humans
- Mad cow disease (Bovine Spongiform Encephalopathy) in cattle
- Scrapie in sheep and goats
- Kuru (once found in humans due to ritual practices)
4. Effects on the Body:
- Loss of brain function
- Memory problems and confusion
- Muscle stiffness and coordination loss
- Ultimately, death
In Simple Words:
Prions are infectious misfolded proteins that make normal proteins in the brain fold the wrong way. This causes damage to nerve cells, leading to severe brain diseases. They are unique because they spread infection without any genetic material — only through abnormal protein structure.