Structural facets of disease-linked human prion protein mutants: a molecular dynamic study

Prion propagation in transmissible spongiform encephalopathies involves the conversion of the cellular prion protein, PrPC, into the pathogenic conformer PrPSc. Human familial forms of the disease are linked to specific mutations in the PrP gene, PRNP, and include Gerstmann-Strussler-Scheinker syndrome (GSS), familial Creutzfeldt-Jakob disease (fCJD), and fatal familial insomnia. To gain insights into the molecular basis of these disorders, we performed 200 ns of classical molecular dynamic simulations in aqueous solution on wild type (WT) human PrP (HuPrP), and on three HuPrP variants located in the globular HuPrP domain: two pathological mutations, HuPrP(Q212P) and HuPrP(E200K), linked to GSS and to fCJD respectively, and one protective polymorphism, HuPrP(E219K) (total time-scale simulated 800 ns). A comparison between the predicted structural determinants of WT HuPrP and HuPrP(E200K) with their NMR structures established the accuracy of the methods used. Strikingly, the analyzed disease-linked variants produced their major effect on the α2-α3 region and the β2-α2 loop, regardless of the mutation position. The conformational change of the latter might affect the interactions with cellular partners in the fibrillation process. The protocol proposed here represents a powerful approach for reproducing the structural effects of genetic mutations located in the globular domain of HuPrP, such as the GSS-related HuPrP(Q212P) and the protective polymorphism HuPrP(E219K).