title: The amino-terminal PrP domain is crucial to modulate prion misfolding and aggregation.
abstract: The main hypothesis for prion diseases is that the cellular protein (PrP(C)) can be altered into a misfolded, beta-sheet-rich isoform (PrP(Sc)), which undergoes aggregation and triggers the onset of transmissible spongiform encephalopathies. Here, we investigate the effects of amino-terminal deletion mutations, rPrP(Delta51-90) and rPrP(Delta32-121), on the stability and the packing properties of recombinant murine PrP. The region lacking in rPrP(Delta51-90) is involved physiologically in copper binding and the other construct lacks more amino-terminal residues (from 32 to 121). The pressure stability is dramatically reduced with decreasing N-domain length and the process is not reversible for rPrP(Delta51-90) and rPrP(Delta32-121), whereas it is completely reversible for the wild-type form. Decompression to atmospheric pressure triggers immediate aggregation for the mutants in contrast to a slow aggregation process for the wild-type, as observed by Fourier-transform infrared spectroscopy. The temperature-induced transition leads to aggregation of all rPrPs, but the unfolding temperature is lower for the rPrP amino-terminal deletion mutants. The higher susceptibility to pressure of the amino-terminal deletion mutants can be explained by a change in hydration and cavity distribution. Taken together, our results show that the amino-terminal region has a pivotal role on the development of prion misfolding and aggregation.
authors.affiliation: Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear de Macromoléculas Jiri Jonas, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: Yraima
authors.initials: Y
authors.lastname: Cordeiro
authors.forename: Julia
authors.initials: J
authors.lastname: Kraineva
authors.forename: Mariana P B
authors.initials: MP
authors.lastname: Gomes
authors.forename: Marilene H
authors.initials: MH
authors.lastname: Lopes
authors.forename: Vilma R
authors.initials: VR
authors.lastname: Martins
authors.forename: Luís M T R
authors.initials: LM
authors.lastname: Lima
authors.forename: Débora
authors.initials: D
authors.lastname: Foguel
authors.forename: Roland
authors.initials: R
authors.lastname: Winter
authors.forename: Jerson L
authors.initials: JL
authors.lastname: Silva
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D019281:Dimerization; D051379:Mice; D046912:Multiprotein Complexes / Q000032:analysis / Q000737:chemistry; D016297:Mutagenesis, Site-Directed; D011328:Prions / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000032:analysis / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D046912:Multiprotein Complexes; D011328:Prions; D011994:Recombinant Proteins