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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 infectious agent is a misfolded form of a host-encoded protein called prion (PrP). Prion proteins are encoded by the Prion Protein Gene . [22] 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.
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.
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 ...
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]
Misfolded proteins can form protein aggregates or amyloid fibrils, get degraded, or refold back to its native structure. In molecular biology, protein aggregation is a phenomenon in which intrinsically-disordered or mis-folded proteins aggregate (i.e., accumulate and clump together) either intra- or extracellularly.
Misfolded prion proteins carry the disease between individuals and cause deterioration of the brain. TSEs are unique diseases in that their aetiology may be genetic, sporadic, or infectious via ingestion of infected foodstuffs and via iatrogenic means (e.g., blood transfusion). [ 7 ]
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]