Prion and non-prion amyloids of the HET-s prion forming domain.
HET-s is a prion protein of the fungus Podospora anserina. A plausible structural model for the infectious amyloid fold of the HET-s prion-forming domain, HET-s(218-289), makes it an attractive system to study structure-function relationships in amyloid assembly and prion propagation. Here, we report on the diversity of HET-s(218-289) amyloids formed in vitro. We distinguish two types formed at pH 7 from fibrils formed at pH 2, on morphological grounds. Unlike pH 7 fibrils, the pH 2 fibrils show very little if any prion infectivity. They also differ in ThT-binding, resistance to denaturants, assembly kinetics, secondary structure, and intrinsic fluorescence. Both contain 5 nm fibrils, either bundled or disordered (pH 7) or as tightly twisted protofibrils (pH 2). We show that electrostatic interactions are critical for the formation and stability of the infectious prion fold given in the current model. The altered properties of the amyloid assembled at pH 2 may arise from a perturbation in the subunit fold or fibrillar stacking.
Sabaté
Raimon
R
Laboratoire de Génétique Moléculaire des Champignons, Institut de Biochimie et de Génétique Cellulaires,UMR 5095 CNRS/Université de Bordeaux 2, 1 rue Camille St Saëns, 33077 Bordeaux cedex, France.
Baxa
Ulrich
U
Benkemoun
Laura
L
Sánchez de Groot
Natalia
N
Coulary-Salin
Bénédicte
B
Maddelein
Marie-Lise
ML
Malato
Laurent
L
Ventura
Salvador
S
Steven
Alasdair C
AC
Saupe
Sven J
SJ
D000595:Amino Acid Sequence; D000682:Amyloid / Q000378:metabolism* / Q000648:ultrastructure*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D048468:Podospora / Q000737:chemistry* / Q000235:genetics; D011328:Prions / Q000378:metabolism* / Q000648:ultrastructure*; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017550:Spectroscopy, Fourier Transform Infrared
D000682:Amyloid; D002352:Carrier Proteins; D011328:Prions