PreSSAPro

OUTPUT EXAMPLES:

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 [Wille et al., 2002].
We report the secondary structure predictions for Syrian hamster and mouse protein prions.



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 [Vilasi et al., 2006] are reported the aggregation rates of horse and bovine apomyoglobins and has been found that crucial substitutions are present in the N-terminal region of this proteins. In this region the horse apomyoglobin shows three mutations respect to the bovine sequence: L9Q, A13V and V21I. These substitutions introduce changes in beta sheet formation propensity, which increase the aggregation rate.
We report the secondary structure predictions for horse and bovine apomyoglobins.