HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) All Versions of this Article: ps.073163308v1 17/3/537    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gerber, R. Articles by James, W. Search for Related Content PubMed PubMed Citation Articles by Gerber, R. Articles by James, W. Social Bookmarking                   What's this?

Conformational pH dependence of intermediate states during oligomerization of the human prion protein

¹ Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
² Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom

(RECEIVED August 7, 2007; FINAL REVISION November 22, 2007; ACCEPTED November 28, 2007)

Intermediate states are key to understanding the molecular mechanisms governing protein misfolding. The human prion protein (PrP) can follow various misfolding pathways, and forms a soluble β-sheet-rich oligomer under acidic, mildly denaturing, high salt conditions. Here we describe a fast conformational switch from the native -monomer to monomeric intermediate states under oligomer-forming conditions, followed by a slower oligomerization process. We observe a pH dependence of the secondary structure of these intermediate forms, with almost native-like -helical secondary structure at pH 4.1 and predominantly β-sheet characteristics at pH 3.6. NMR spectroscopy differentiates these intermediate states from the native protein and indicates dynamic rearrangements of secondary structure elements characteristic of a molten globule. The -helical intermediate formed at pH 4.1 can convert to the β-sheet conformation at pH 3.6 but not vice versa, and neither state can be reconverted to an -monomer. The presence of methionine rather than valine at codon 129 accelerates the rate of oligomer formation from the intermediate state.

Keywords: prion protein; misfolding; intermediates; oligomer; polymorphism

Reprint requests to: Remo Gerber, Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK; e-mail: remo.gerber{at}lincoln.oxon.org; fax: +44 1865-285756.

Abbreviations: PrP, prion protein; PrP^C, cellular PrP; PrP^Sc, scrapie misfolded PrP; NMR, nuclear magnetic resonance; sec-HPLC, size exclusion high performance liquid chromatography; CD, circular dichroism; HSQC, hetero-nuclear single quantum coherence.

Article published online ahead of print. Article and publication date are at http://www.proteinscience.org/cgi/doi/10.1110/ps.073163308.

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?