Contribution of two conserved glycine residues to fibrillogenesis of the 106-126 prion protein fragment. Evidence that a soluble variant of the 106-126 peptide is neurotoxic.
The fibrillogenic peptide corresponding to the residues 106-126 of the prion protein sequence (PrP 106-126) is largely used to explore the neurotoxic mechanisms underlying the prion disease. However, whether the neuronal toxicity of PrP 106-126 is caused by a soluble or fibrillar form of this peptide is still unknown. The aim of this study was to correlate the structural state of this peptide with its neurotoxicity. Here we show that the two conserved Gly114 and Gly119 residues, in force of their intrinsic flexibility, prevent the peptide assuming a structured conformation, favouring its aggregation in amyloid fibrils. The substitution of both Gly114 and Gly119 with alanine residues (PrP 106-126 AA mutated peptide) reduces the flexibility of this prion fragment and results in a soluble, beta-structured peptide. Moreover, PrP 106-126 AA fragment was highly toxic when incubated with neuroblastoma cells, likely behaving as a neurotoxic protofibrillar intermediate of the wild-type PrP 106-126. These data further confirm that the fibrillar aggregation is not necessary for the induction of the toxic effects of PrP 106-126.
Florio
Tullio
T
Department Oncology, Biology and Genetics, Sect. Pharmacology, University of Genova, Italy.
Paludi
Domenico
D
Villa
Valentina
V
Principe
Daniela Rossi
DR
Corsaro
Alessandro
A
Millo
Enrico
E
Damonte
Gianluca
G
D'Arrigo
Cristina
C
Russo
Claudio
C
Schettini
Gennaro
G
Aceto
Antonio
A
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D017124:Conserved Sequence; D005998:Glycine / Q000737:chemistry*; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009447:Neuroblastoma / Q000188:drug therapy; D009498:Neurotoxins / Q000737:chemistry / Q000633:toxicity; D010446:Peptide Fragments / Q000737:chemistry* / Q000633:toxicity*; D017096:Prion Diseases / Q000209:etiology; D011328:Prions / Q000737:chemistry* / Q000633:toxicity*; D017433:Protein Structure, Secondary / Q000502:physiology; D012995:Solubility; D013329:Structure-Activity Relationship
D046911:Macromolecular Substances; D009498:Neurotoxins; D010446:Peptide Fragments; D011328:Prions; C082632:prion protein (106-126); D005998:Glycine