Solution Structure of a 142-Residue Recombinant Prion Protein Corresponding to the Infectious Fragment of the Scrapie Isoform

The scrapie prion protein (PrPSc) is the major, and possibly the only, component of the infectious prion; it is generated from the cellular isoform (PrPC) by a conformational change. N-terminal truncation of PrPScby limited proteolysis produces a protein of ≈ 142 residues designated PrP 27-30, which...

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Published in:Proceedings of the National Academy of Sciences - PNAS 1997-09, Vol.94 (19), p.10086-10091
Main Authors: James, Thomas L., Liu, He, Ulyanov, Nikolai B., Farr-Jones, Shauna, Zhang, Hong, Donne, David G., Kaneko, Kiyotoshi, Groth, Darlene, Mehlhorn, Ingrid, Prusiner, Stanley B., Cohen, Fred E.
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Bacteria
Biochemistry
Biological Sciences
Chemical equilibrium
Connectivity
Creutzfeldt Jakob syndrome
Cricetinae
Crystallography, X-Ray
Epitopes
Humans
Isotope Labeling
Magnetic Resonance Spectroscopy
Mesocricetus
Molecular Sequence Data
Prion diseases
Prions
Prions - chemistry
Prions - pathogenicity
Protein isoforms
Protein Structure, Secondary
Proteins
Protons
Recombinant Proteins - chemistry
Scrapie - metabolism
Sheep
Solutions
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Summary:The scrapie prion protein (PrPSc) is the major, and possibly the only, component of the infectious prion; it is generated from the cellular isoform (PrPC) by a conformational change. N-terminal truncation of PrPScby limited proteolysis produces a protein of ≈ 142 residues designated PrP 27-30, which retains infectivity. A recombinant protein (rPrP) corresponding to Syrian hamster PrP 27-30 was expressed in Escherichia coli and purified. After refolding rPrP into an α -helical form resembling PrPC, the structure was solved by multidimensional heteronuclear NMR, revealing many structural features of rPrP that were not found in two shorter PrP fragments studied previously. Extensive side-chain interactions for residues 113-125 characterize a hydrophobic cluster, which packs against an irregular β -sheet, whereas residues 90-112 exhibit little defined structure. Although identifiable secondary structure is largely lacking in the N terminus of rPrP, paradoxically this N terminus increases the amount of secondary structure in the remainder of rPrP. The surface of a long helix (residues 200-227) and a structured loop (residues 165-171) form a discontinuous epitope for binding of a protein that facilitates PrPScformation. Polymorphic residues within this epitope seem to modulate susceptibility of sheep and humans to prion disease. Conformational heterogeneity of rPrP at the N terminus may be key to the transformation of PrPCinto PrPSc, whereas the discontinuous epitope near the C terminus controls this transition.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.94.19.10086