Prion protein: Difference between revisions
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The prion protein (PrP) is a cell surface glycoprotein, which can exist in two alternatively folded confirmations: the cellular isoform (PrP<sup>C</sup>) can undergo a structural conversion to a 'scrapie' or disease associated isoform termed PrP<sup>Sc</sup>. Prion diseases | The prion protein (PrP) is a cell surface glycoprotein, which can exist in two alternatively folded confirmations: the cellular isoform (PrP<sup>C</sup>) can undergo a structural conversion to a 'scrapie' or disease associated isoform termed PrP<sup>Sc</sup>. | ||
=Prion diseases= | |||
The naturally ocuring prion diseases include Creutzfeldt Jakob disease (CJD) in people, bovine spongiform encephalopathy (BSE) commonly known as "mad cow" disease,scpie in sheep and goats, and chronic wasting disease in cervids. | |||
are characterterized by aggregates of PrP<sup>Sc</sup>. | |||
The spontaneous, genetic and infectious etiologies of prion diseases can be explained by a simple protein-based model in which PrP<sup>C</sup> is converted into PrP<sup>Sc</sup>, which then initiates autocatalytic refolding of PrP<sup>C</sup> in a template-dependent manner. | |||
In sporadic disease, the spontaneous refolding or misfolding of PrP<sup>C</sup> into PrP<sup>Sc</sup> initiates the cascade. In genetic prion diseases, point mutations in PrP make this more likely to happen than in the wild type protein, Infectious etiology is explained by introduction of exogenous PrP<sup>Sc</sup> which then initiated refolding of endogenous PrP<sup>C</sup>. | |||
=Structure of PrP<sup>C</sup>= | =Structure of PrP<sup>C</sup>= | ||
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=Models of PrP<sup>Sc</sup> structure= | =Models of PrP<sup>Sc</sup> structure= | ||
Circular dichroism studies first demonstrated that PrP<sup>Sc</sup> had very different proportions of α-helices and β-sheet to PrP<sup>C</sup> | Circular dichroism studies first demonstrated that PrP<sup>Sc</sup> had very different proportions of α-helices and β-sheet to PrP<sup>C</sup> | ||
There are a number of technical obstacles in determining the molecular structure of PrP(sup)Sc</sup> | There are a number of technical obstacles in determining the molecular structure of PrP(sup)Sc</sup> | ||