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Prions consist of a misfolded form of major prion protein (PrP), a protein that is a natural part of the bodies of humans and other animals. The PrP found in infectious prions has a different structure and is resistant to proteases , the enzymes in the body that can normally break down proteins.
The two forms of prion are designated as PrP c, which is a normally folded protein, and PrP sc, a misfolded form which gives rise to the disease. The two forms do not differ in their amino acid sequence; however, the pathogenic PrP sc isoform differs from the normal PrP c form in its secondary and tertiary structure.
Prions cannot be transmitted through the air, through touching, or most other forms of casual contact. However, they may be transmitted through contact with infected tissue, body fluids, or contaminated medical instruments. Normal sterilization procedures such as boiling or irradiating materials fail to render prions non-infective. However ...
In medicine, proteinopathy ([pref. protein]; -pathy [suff. disease]; proteinopathies pl.; proteinopathic adj), or proteopathy, protein conformational disorder, or protein misfolding disease, is a class of diseases in which certain proteins become structurally abnormal, and thereby disrupt the function of cells, tissues and organs of the body.
Infectious prions are misfolded proteins that can cause normally folded proteins to also become misfolded. [4] About 85% of cases of CJD occur for unknown reasons, while about 7.5% of cases are inherited in an autosomal dominant manner. [4] [9] Exposure to brain or spinal tissue from an infected person may also result in spread. [4]
The abnormal protein PrP Sc accumulates in the brain and destroys nerve cells, which leads to the mental and behavioral features of prion diseases. [citation needed] Several other changes in the PRNP gene (called polymorphisms) do not cause prion diseases but may affect a person's risk of developing these diseases or alter the course of the ...
Chronic wasting disease (CWD), sometimes called zombie deer disease, is a transmissible spongiform encephalopathy (TSE) affecting deer.TSEs are a family of diseases thought to be caused by misfolded proteins called prions and include similar diseases such as BSE (mad cow disease) in cattle, Creutzfeldt–Jakob disease (CJD) in humans, and scrapie in sheep. [2]
Mathias Jucker and Lary Walker have likened this process to the formation and spread of prions in diseases known as spongiform encephalopathies or prion diseases. [36] [37] According to the prion paradigm, certain proteins misfold into shapes that are rich in beta-sheet secondary structure. [7] [38]