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quote:Originally posted by Big_JulesTo add another layer to this discussion, there is variation in the sequence of bases in the gene and hence the sequence of amino acids (building blocks) in normal prion protein among any animal species, including us. Such differences also confer a greater disposition to heritable neurodegenerative diseases such as conventional CJD. It appears that certain of these variations make the normal prion protein more or less susceptible to confirmational change induced by the 'rogue' prion protein. Several of these sequences have been identified. Presumably, interaction between key amino acid sequences in the rogue and normal proteins enact the conformational change. As Chris has stated, the beta-sheet conformation appears to be highly resistant to enzymatic digestion, so that enzymatic digestion, specially within neural tissue, is unlikely. With respect to antibodies, one would imagine that the indigenous protein, while changed in shape, would still be recognised as 'self' and not susceptible to immune attack.
quote:Originally posted by meeChris, could you please explain your position further as it seems confusing to me what you are trying to say. Are you saying that the prions convert the normal proteins directly? What would be the mechanism? If normal and abnormal proteins were placed in a dish together, would they all become abnormal? I would think a cellular process would be necessary for the conversion. Why would the abnormal protein be selected for if it is not somehow more efficient to process them?
quote:Originally posted by TomG1987Hm, you misunderstand me chris, i mean how did the initial molecule of PrPsc come into being. Because mutation of dna would cause such a change in PrPc to make it abrnomal, and also paired with the fact that only one in hundreds of billions of PrPc molecules flip spontaneously into PrPsc. So it makes sense some mutugen causes a problem during translation or transcription (more than likely in translation) that would create the first PrPsc molecule.
quote:Originally posted by christhe structure of PrP is well established and the switch to a pathological (scrapie) form involves a conformational change from a predominantly globular to a beta-pleated sheet architecture. As such, this fibrous beta-pleated sheet structure is extremely stable and resilient to most degradative mechanisms. It is for this reason that contaminated neurosurgical instruments proved so difficult to disinfect and are now routinely destroyed after a procedure.
quote:Originally posted by bezoarAnd so, what's the rest of the story? Did he receive monoclonal antibodies, and if so, was he cured or was the disease held in check?Bezoar
quote:Originally posted by chris...jelly (what Americans call jello for some reason, probably because they call jam jelly, god knows why)...