Solid-state NMR studies of the secondary structure of a mutant prion protein fragment of 55 residues that induces neurodegeneration.
The secondary structure of a 55-residue fragment of the mouse prion protein, MoPrP(89-143), was studied in randomly aggregated (dried from water) and fibrillar (precipitated from water/acetonitrile) forms by (13)C solid-state NMR. Recent studies have shown that the fibrillar form of the P101L mutant of MoPrP(89-143) is capable of inducing prion disease in transgenic mice, whereas unaggregated or randomly aggregated samples do not provoke disease. Through analysis of (13)C chemical shifts, we have determined that both wild-type and mutant sequence MoPrP(89-143) form a mixture of beta-sheet and alpha-helical conformations in the randomly aggregated state although the beta-sheet content in MoPrP(89-143, P101L) is significantly higher than in the wild-type peptide. In a fibrillar state, MoPrP(89-143, P101L) is completely converted into beta-sheet, suggesting that the formation of a specific beta-sheet structure may be required for the peptide to induce disease. Studies of an analogous peptide from Syrian hamster PrP verify that sequence alterations in residues 101-117 affect the conformation of aggregated forms of the peptides.
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Department of Chemistry, University of California, Berkeley, CA 94720, USA.
Bitter
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Liu
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Ball
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Kaneko
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Wille
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Cohen
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Prusiner
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Pines
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Wemmer
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D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D002247:Carbon Isotopes; D007553:Isotope Labeling / Q000379:methods; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010446:Peptide Fragments / Q000737:chemistry*; D018621:PrPC Proteins / Q000737:chemistry*; D017096:Prion Diseases; D011328:Prions / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment
D002247:Carbon Isotopes; D010446:Peptide Fragments; D018621:PrPC Proteins; D011328:Prions