The α-Helical C-Terminal Domain of Full-Length Recombinant PrP Converts to an In-Register Parallel β-Sheet Structure in PrP Fibrils: Evidence from Solid State Nuclear Magnetic Resonance

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• 作者：Robert Tycko ; Regina Savtchenko ; Valeriy G. Ostapchenko ; Natallia Makarava ; Ilia V. Baskakov
• 刊名：Biochemistry
• 出版年：2010
• 出版时间：November 9, 2010
• 年：2010
• 卷：49
• 期：44
• 页码：9488-9497
• 全文大小：1067K
• 年卷期：v.49,no.44(November 9, 2010)
• ISSN：1520-4995

文摘

We report the results of solid state nuclear magnetic resonance (NMR) measurements on amyloid fibrils formed by the full-length prion protein PrP (residues 23−231, Syrian hamster sequence). Measurements of intermolecular ¹³C−¹³C dipole−dipole couplings in selectively carbonyl-labeled samples indicate that β-sheets in these fibrils have an in-register parallel structure, as previously observed in amyloid fibrils associated with Alzheimer’s disease and type 2 diabetes and in yeast prion fibrils. Two-dimensional ¹³C−¹³C and ¹⁵N−¹³C solid state NMR spectra of a uniformly ¹⁵N- and ¹³C-labeled sample indicate that a relatively small fraction of the full sequence, localized to the C-terminal end, forms the structurally ordered, immobilized core. Although unique site-specific assignments of the solid state NMR signals cannot be obtained from these spectra, analysis with a Monte Carlo/simulated annealing algorithm suggests that the core is comprised primarily of residues in the 173−224 range. These results are consistent with earlier electron paramagnetic resonance studies of fibrils formed by residues 90−231 of the human PrP sequence, formed under somewhat different conditions [Cobb, N. J., Sonnichsen, F. D., McHaourab, H., and Surewicz, W. K. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 18946−18951], suggesting that an in-register parallel β-sheet structure formed by the C-terminal end may be a general feature of PrP fibrils prepared in vitro.