Progress towards structural understanding of infectious sheep PrP-amyloid.

ABSTRACT: The still elusive structural difference of non-infectious and infectious amyloid of the mammalian prion protein (PrP) is a major pending milestone in understanding protein-mediated infectivity in neurodegenerative diseases. Preparations of PrP-amyloid proven to be infectious have never been investigated with a high-resolution technique. All available models to date have been based on low-resolution data. Here, we establish protocols for the preparation of infectious samples of full-length recombinant (rec) PrP-amyloid in NMR-sufficient amounts by spontaneous fibrillation and seeded fibril growth from brain extract. We link biological and structural data of infectious recPrP-amyloid, derived from bioassays, atomic force microscopy, and solid-state NMR spectroscopy. Our data indicate a semi-mobile N-terminus, some residues with secondary chemical shifts typical of ?-helical secondary structure in the middle part between ?115 to ?155, and a distinct ?-sheet core C-terminal of residue ?155. These findings are not in agreement with all current models for PrP-amyloid. We also provide evidence that samples seeded from brain extract may not differ in the overall arrangement of secondary structure elements, but rather in the flexibility of protein segments outside the ?-core region. Taken together, our protocols provide an essential basis for the high-resolution characterization of non-infectious and infectious PrP-amyloid in the near future.

SUBMITTER: Muller H 

PROVIDER: S-EPMC4601355 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature