Solution NMR structures of disease-linked human prion protein mutants

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a group of rare neuropathies characterized by a spongiform neurodegeneration of the central nervous system caused by prions. These disorders include Creutzfeldt–Jakob disease (CJD), Gerstmann-Sträussler-Scheinker (GSS) syndrome, Fatal Familial Insomnia and kuru in humans, bovine spongiform encephalopathy in cattle, scrapie in sheep and goats, and chronic wasting disease in elk, deer and moose. Prions are thought to consist solely of a misfolded isoform (PrPSc) of the normal, host-encoded cellular protein (PrPC), whose function is still unknown. Human (Hu) PrPC is a 209 residues long glycoprotein, tethered to the outer leaflet of the plasma membrane by a glycosylphosphatidylinositol (GPI) anchoring and its primary structure is highly conserved among mammals. According to the „protein-only hypothesis‟, during the course of prion diseases, PrPC is converted into the abnormal form by a conversion process whereby most α-helix motives are replaced by β-sheet secondary structures. One of the strongest arguments supporting the „protein-only hypothesis‟ is the link between inherited prion diseases and mutations in the PRNP gene. In our recent studies, we have determined the NMR solution-state structures of the truncated recombinant human (Hu) PrPs carrying the pathological Q212P (90-231, M129) 1 and V210I (90-231, M129) 2 mutations linked to GSS and genetic CJD, respectively. In order to determine high-resolution structures triple resonance (1H, 13C and 15N) NMR experiments were performed using 800 MHz NMR spectrometer. The determined structures of both mutants consist of unstructured N-terminal part (residues 90-124) and well-defined C-terminal domain (residues 125-228). The C-terminal part contains …