Example 1:
PrP protein is associated to the onset of a family of diseases named Transmissible Spongiform Encephalophaties
(TSE) by a mechanism involving the conversion of a soluble (cellular) form, PrPC, into an insoluble (scrapie)
variant, PrPSc, which is deemed to also retain an intrinsic infectivity. These two isomers of PrP,
while indistinguishable from a chemical point of view, substantially differ in their secondary structures.
Indeed, PrPC is predominantly alpha-helical with little beta-sheet contribution, whereas PrPSc
has a considerably higher beta-sheet content.
According to this model, prion diseases are thus caused by a drastic conformational rearrangement of the cellular
form into proteinase K resistant amyloidogenic and beta-sheet containing. Because the insolubility of the scrapie form has
frustated structural studies by X-Ray crystallography or NMR spectroscopy, the electron crystallography was used to
characterize the structure of Syrian hamster and mouse prions [
We report the secondary structure predictions for
Example 2:
The apomyoglobin is a globular protein which contains only alpha-helical structures. Many studies have demostrated
that this protein forms amyloid fibrils due to association of unfolded polypeptide segments
if specific residues are mutated or if is incubated at pH 9.0 and at 65°C.
Peptide fragments corresponding to the N-terminal region or to G-helix (100-120)
of Mb have been previously shown to form species with extensive beta-structure.
In a recent paper
[
We report the secondary structure predictions for