Assembly of the full-length recombinant mouse prion protein I. Formation of soluble oligomers.
The conversion of a monomeric alpha-helix-rich isoform to multimeric beta-sheet-rich isoforms is a prominent feature of the conversion between PrP(C) and PrP(SC). We mimicked this process in vitro by exposing an unglycosylated recombinant form of the full-length mouse prion protein ((Mo)PrP(23-231)) to an acidic pH, at 37 degrees C, and we monitored the kinetics of conformational change and assembly. In these conditions, monomeric (Mo)PrP(23-231) converts slowly to two ensembles of soluble oligomers that are separated by size exclusion chromatography. The larger oligomers (I) are unstable, and their formation involves almost no change in secondary structure content. The smaller oligomers (II) form stable spherical or annular particles containing between 8 and 15 monomers as determined by multi-angle laser light scattering (MALLS). Their formation is concomitant with the main, thought limited, change in the secondary structure content (10%) seen by Fourier Transform Infrared (FTIR) spectroscopy. Even if these oligomers conserve a large part of the secondary structure of monomeric PrP, they exhibit amyloid features with the appearance of intermolecular beta-structure as revealed by the appearance of an IR band below 1620 cm(-1).
Laboratoire de Biophysique Moléculaire et Cellulaire, Université Joseph Fourier, BMC/DRDC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
Charlotte
C
Vendrely
Hélène
H
Valadié
Lucie
L
Bednarova
Laurent
L
Cardin
Marielle
M
Pasdeloup
Jéremy
J
Cappadoro
Jan
J
Bednar
Marguerite
M
Rinaudo
Marc
M
Jamin
D000818:Animals; D002850:Chromatography, Gel; D002942:Circular Dichroism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D051379:Mice; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D011328:Prions / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011489:Protein Denaturation; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D012995:Solubility; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
D010446:Peptide Fragments; D011328:Prions; D020033:Protein Isoforms; D011994:Recombinant Proteins