Structural and hydration properties of the partially unfolded states of the prion protein.

ABSTRACT: Misfolding and aggregation of the prion protein (PrP) is responsible for the development of transmissible spongiform encephalopathies (TSE). To gain insights into possible aggregation-prone intermediate states, we construct the free energy surface of the C-terminal globular domain of the PrP from enhanced sampling of replica exchange molecular dynamics. This cellular domain is characterized by three helices H1-H3 and a small beta-sheet. In agreement with experimental studies, the partially unfolded states display a stable core built from the central portions of helices H2 and H3 and a high mobility of helix H1 from the core. Among all identified conformational basins, a marginally populated state appears to be a very good candidate for aggregation. This intermediate is stabilized by four TSE-sensitive key interactions, displays a longer helix H1 with both a dry and solvated surface, and is featured by a significant detachment of helix H1 from the PrP-core.

SUBMITTER: De Simone A 

PROVIDER: S-EPMC1929054 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature