Structural properties of Gerstmann-Straussler-Scheinker disease amyloid protein.
Prion protein (PrP) amyloid formation is a central feature of genetic and acquired forms of prion disease such as Gerstmann-Sträussler-Scheinker disease (GSS) and variant Creutzfeldt-Jakob disease. The major component of GSS amyloid is a PrP fragment spanning residues approximately 82-146. To investigate the determinants of the physicochemical properties of this fragment, we synthesized PrP-(82-146) and variants thereof, including entirely and partially scrambled peptides. PrP-(82-146) readily formed aggregates that were partially resistant to protease digestion. Peptide assemblies consisted of 9.8-nm-diameter fibrils having a parallel cross-beta-structure. Second derivative of infrared spectra indicated that PrP-(82-146) aggregates are primarily composed of beta-sheet (54%) and turn (24%) which is consistent with their amyloid-like properties. The peptide induced a remarkable increase in plasma membrane microviscosity of primary neurons. Modification of the amino acid sequence 106-126 caused a striking increase in aggregation rate, with formation of large amount of protease-resistant amorphous material and relatively few amyloid fibrils. Alteration of the 127-146 region had even more profound effects, with the inability to generate amyloid fibrils. These data indicate that the intrinsic properties of PrP-(82-146) are dependent upon the integrity of the C-terminal region and account for the massive deposition of PrP amyloid in GSS.
Salmona
Mario
M
Istituto di Ricerche Farmacologiche Mario Negri, Via Eritrea 62, 20157 Milan, Italy. salmona@marionegri.it
Morbin
Michela
M
Massignan
Tania
T
Colombo
Laura
L
Mazzoleni
Giulia
G
Capobianco
Raffaella
R
Diomede
Luisa
L
Thaler
Florian
F
Mollica
Luca
L
Musco
Giovanna
G
Kourie
Joseph J
JJ
Bugiani
Orso
O
Sharma
Deepak
D
Inouye
Hideyo
H
Kirschner
Daniel A
DA
Forloni
Gianluigi
G
Tagliavini
Fabrizio
F
D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003224:Congo Red / Q000494:pharmacology; D010450:Endopeptidases / Q000494:pharmacology; D016098:Gerstmann-Straussler-Scheinker Disease / Q000378:metabolism*; D006801:Humans; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011328:Prions / Q000737:chemistry*; D020033:Protein Isoforms; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D014961:X-Ray Diffraction
D000682:Amyloid; D010446:Peptide Fragments; D010455:Peptides; D011328:Prions; D020033:Protein Isoforms; C477930:prion protein (82-146); D003224:Congo Red; D010450:Endopeptidases