Beta-sheet core of human prion protein amyloid fibrils as determined by hydrogen/deuterium exchange.
Propagation of transmissible spongiform encephalopathies is associated with the conversion of normal prion protein, PrP(C), into a misfolded, oligomeric form, PrP(Sc). Although the high-resolution structure of the PrP(C) is well characterized, the structural properties of PrP(Sc) remain elusive. Here we used MS analysis of H/D backbone amide exchange to examine the structure of amyloid fibrils formed by the recombinant human PrP corresponding to residues 90-231 (PrP90-231), a misfolded form recently reported to be infectious in transgenic mice overexpressing PrP(C). Analysis of H/D exchange data allowed us to map the systematically H-bonded beta-sheet core of PrP amyloid to the C-terminal region (staring at residue approximately 169) that in the native structure of PrP monomer corresponds to alpha-helix 2, a major part of alpha-helix 3, and the loop between these two helices. No extensive hydrogen bonding (as indicated by the lack of significant protection of amide hydrogens) was detected in the N-terminal part of PrP90-231 fibrils, arguing against the involvement of residues within this region in stable beta-structure. These data provide long-sought experimentally derived constraints for high-resolution structural models of PrP amyloid fibrils.
Lu
Xiaojun
X
Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA.
Wintrode
Patrick L
PL
Surewicz
Witold K
WK
D000682:Amyloid / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003903:Deuterium / Q000737:chemistry; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D013058:Mass Spectrometry; D010449:Peptide Mapping; D010455:Peptides / Q000737:chemistry; D017096:Prion Diseases / Q000378:metabolism*; D011328:Prions / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D000682:Amyloid; D010455:Peptides; D011328:Prions; D006859:Hydrogen; D003903:Deuterium