NMR characterization of the pH 4 β-intermediate of the prion protein: the N-terminal half of the protein remains unstructured and retains a high degree of flexibility

O'Sullivan, Denis B. D., Jones, Christopher E., Abdelraheim, Salama R., Thompsett, Andrew R., Brazier, Marcus W., Toms, Harold, Brown, David R. and Viles, John H. (2007) NMR characterization of the pH 4 β-intermediate of the prion protein: the N-terminal half of the protein remains unstructured and retains a high degree of flexibility. Biochemical Journal, 401 2: 533-540. doi:10.1042/BJ20060668


Author O'Sullivan, Denis B. D.
Jones, Christopher E.
Abdelraheim, Salama R.
Thompsett, Andrew R.
Brazier, Marcus W.
Toms, Harold
Brown, David R.
Viles, John H.
Title NMR characterization of the pH 4 β-intermediate of the prion protein: the N-terminal half of the protein remains unstructured and retains a high degree of flexibility
Journal name Biochemical Journal   Check publisher's open access policy
ISSN 0264-6021
1470-8728
Publication date 2007-01-15
Sub-type Article (original research)
DOI 10.1042/BJ20060668
Open Access Status Not Open Access
Volume 401
Issue 2
Start page 533
End page 540
Total pages 8
Place of publication London, United Kingdom
Publisher Portland Press
Language eng
Formatted abstract
Prion diseases are associated with the misfolding of the PrP (prion protein) from a largely α-helical isoform to a β-sheet-rich oligomer. CD has shown that lowering the pH to 4 under mildly denaturing conditions causes recombinant PrP to convert from an α-helical protein into one that contains a high proportion of β-sheet-like conformation. In the present study, we characterize this soluble pH 4 folding intermediate using NMR. 15N-HSQC (heteronuclear single-quantum correlation) studies with mPrP (mouse PrP)-(23-231) show that a total of 150 dispersed amide signals are resolved in the native form, whereas only 65 amide signals with little chemical shift dispersion are observable in the pH4 form. Three-dimensional 15N-HSQC-TOCSY and NOESY spectra indicate that the observable residues are all assigned to amino acids in the N-terminus: residues 23-118. 15N transverse relaxation measurements indicate that these N-terminal residues are highly flexible with additional fast motions. These observations are confirmed via the use of truncated mPrP-(112-231), which shows only 16 15N-HSQC amide peaks at pH 4. The loss of signals from the C-terminus can be attributed to line broadening due to an increase in the molecular size of the oligomer or exchange broadening in a molten-globule state.
Keyword CD spectroscopy
Folding intermediate
Prion protein (PrP)
Secondary structure
Translational diffusion
T2 relaxation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
 
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