Mad cow disease.

Groundbreaking research has identified the structure of the infectious prion protein, the cause of 'mad cow disease' or BSE, chronic wasting disease in deer and elk and Creutzfeldt-Jakob disease in humans, The infectious prion protein is a misfolded protein, which makes it very difficult to purify and study. Since it clumps together, standard structural biology techniques cannot be used to study it. Since the protein was first purified in the 1980s researchers have made limited insights into the structure of the protein. The collaborative study, published in PLOS Pathogens, used electron cryomicroscopy to collect high-resolution electron micrographs. This was the first time this technology has been used on amyloid fibrils of the infectious prion, which are a special form of clumped-together proteins that form fibrils. The team had to develop a processing scheme for the data masses. There were thousands of electron micrographs, and they had to extract the best images.The model can give insights into how the infectious prion protein propagates. The structure argues against existing theories of prion conversion and suggests how the process might actually work. The study suggests how infectious prions replicate by converting non-infectious, cellular versions into copies of themselves. Moving forward, the researchers want to go into more depth. This study used model system prions, but they are now using the prions that infect cows (BSE), wild animals (Chronic Wasting Disease) and humans (Creutzfeldt-Jakob Disease).continue