Chirality of the disulfide in the prion proteins.

In the Transmissible Spongiform Encephalopathies (TSEs) it has been generally assumed that the normal prion proteins (PPr) occurring on neural cells have the same composition of amino acids and the same sequence as the pathological forms (PPrSc) but differ in the manner of folding. The mechanism(s) by which the conversion of PPr into PPrSc takes place remain unknown. This paper calls attention to some aspects of chirality inherent in the disulfide function and suggests the possibility that handedness in the disulfide bond of prions may transmit stereochemical information that can influence the manner of folding or refolding into pathogenic forms.