Dynamic Diagnosis of Familial Prion Diseases Supports the beta 2-alpha 2 Loop as a Universal Interference Target

Background: Mutations in the cellular prion protein associated to familial prion disorders severely increase the likelihood of its misfolding into pathogenic conformers. Despite their postulation as incompatible elements with the native fold, these mutations rarely modify the native state structure. However they variably have impact on the thermodynamic stability and metabolism of PrP(C) and on the properties of PrP(Sc) aggregates. To investigate whether the pathogenic mutations affect the dynamic properties of the HuPrP(125-229) alpha-fold and find possible common patterns of effects that could help in prophylaxis we performed a dynamic diagnosis of ten point substitutions. Methodology/Principal Findings: Using all-atom molecular dynamics simulations and novel analytical tools we have explored the effect of D178N, V180I, T183A, T188K, E196K, F198S, E200K, R208H, V210I and E211Q mutations on the dynamics of HuPrP(125-228) alpha-fold. We have found that while preserving the native state, all mutations produce dynamic changes which perturb the coordination of the alpha 2-alpha 3 hairpin to the rest of the molecule and cause the reorganization of the patches for intermolecular recognition, as the disappearance of those for conversion inhibitors and the emergence of an interaction site at the beta 2-alpha 2 loop region. Conclusions/Significance: Our results suggest that pathogenic mutations share a common pattern of dynamical alterations that converge to the conversion of the beta 2-alpha 2 loop into an interacting region that can be used as target for interference treatments in genetic diseases.