Prions : The Infectious Protein Agent

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What causes Mad Cow Disease? Prions. Prions are also behind other neurodegenerative diseases such as the Creutzfeldt-Jakob disease, Kuru, Gerstmann-Straussler-Scheinker disease and some forms of fatal insomnia. These are all prions diseases that have been found to exist in humans. The prion disease for cattle is what we know as the Mad Cow Disease. Prions also exist in other animals such as sheep, mink, mule deer, elk, cats, and some others.

So what's so special about prions? Unlike other neurodegenerative diseases that are caused by the misfolding of proteins, altered proteins, abnormal gene splicing, improper expression, or ineffective clearing of proteins which slowly leads to disease by accumulation, prions cause disease by acting as an infectious agent. One abnormal prion protein is enough to turn all the normal prion proteins present into itself.

How do prions do that? Scientists are still unsure of how exactly one protein is capable of turning another protein into itself. Many experiments are conducted to help shed light on its mysterious capabilities. In this website, we hope to explain one of these experiments that involved the effect of pH on the structure of prion proteins.

Wait...Prions? Prion Protein? Which is which? Prions is the name assigned to infectious protein agents. Prion protein (PrPC) is the normal cellular protein that can become an infectious agent.

The Official Mad Cow Disease Home Page The prion is a newly discovered pathogen that is vastly different from the known pathogens of today; namely viruses and bacteria. Unlike the bacteria, no antibiotics can cure prions. They are not typical of a prokaryotic organism or a eukaryotic organism, all that is present in this pathogen is the protein PrPSc. This is the mutated form of the protein PrPC, which is encoded by a chromosomal gene. These two proteins differ in their spatial protein structures and their susceptibility to enzyme digestion. PrPC is completely destroyed in enzyme digestion, whereas PrPSc is resistant to any form of digestion.Viruses usually have nucleic acid, protein, and other constituents that aid in the creation of more progeny viruses. As far as prions are concerned, they multiply by infecting the PrPC protein and turning it into a complex such as itself, the PrPSc protein. Prions exist in multiple molecular forms whereas viruses exist in a single form with distinct ultrastructural morphology.Another difference between the virus and the prion is that viruses almost always provoke an immune response in the host that it is infecting.