Prions

• prions are disease causing proteins which act as self-propagating, infectious agents
• prions cause the spread of neurodegenerative disease like Scrapie in

  sheep, Bovine Spongiform Encephalopathy (BSE) in cattle and Creutzfeldt-

  Jakob Disease (CJD) in humans.
• These proteins in prions can fold in multiple, structurally distinct ways as a result of changes in their secondary structure,

  giving a protein rich in tightly packed B-pleated sheets.
• the misfolding in the proteins are transmitted to other proteins making them infected also

  (Dominos- knock of series and events that escalate)
• Transmission can occur through

  Consumption of infected food,

  Open wound contaminated with soi

  Medical procedure involving infected material
• infection can also happen from:

  Inheritance from gene mutation (during meiosis from sperm/egg)

  Inherited prion disease account for 15% of CJD cases.
• Infection can also happen

  Sporadically(randomly) whereby spontaneous transformations occur turning normal proteins into disease causing
• The acronym for the normal structure of proteins is PrP c (2 nd structure alpha helix) into
• The acronym for a diseased protein is PrP sc (2 nd

  structure Beta sheets).
• Once formed, prions are extremely stable.

  They accumulate in the brain and

  in other neural tissue, affecting their structure.

  Meaning they're resistant to denaturation,

  so very hard to treat.
• neurological tissue (e.g. brain and spinal cord) is banned in human and animal food chain to stop prions