Structure, function and interactions of prion proteins and prion protein domains

• Research unit: EU RFP
• Project number: 97.0578-1

Key words (English)

Transmissible spongiform ecephalopathies; prion diseases; protein folding; protein conformation

Alternative project number (English)

EU project number: BMH4-CT98-6051

Research programs (English)

EU-programme: 4. Frame Research Programme - 4.2 Agriculture and agroindustry

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
ETH Zürich
Institut für Molekularbiologie und Biophysik

Partners and International Organizations (English)

Coordinator: Universität Göttingen (D)

Abstract (English)

Towards the goal of understanding the conformational transition of the cellular prion protein PrPC to its scrapie-isoform PrPSc, the supposed key event in the propagation of the infectious agent of mammalian prion diseases, we are studying the biophysical properties and structural plasticity of recombinant murine PrP, mPrP(23-231). Analysis of folding of mPrP(23-231) under a large variety of conditions in vitro revealed that the protein forms a scrapie-like unfolding intermediate at pH 4.0, moderate denaturant concentrations, and ionic strengths above 50 mM. Moreover, the unfolding intermediate is oligomeric, as it is only populated at protein concentrations above 15 mM. These data indicate that the intermediate may also be formed in vivo during endocytosis of PrPC and represent a small, oligomeric precursor of PrPSc. The ability of forming the intermediate is an intrinsic property of the structured, C-terminal domain of the prion protein, because the isolated domain PrP(121-231) forms the unfolding intermediate under exactly the same condition as the full-length protein. As PrPC has been proposed to be a copper (II) binding protein in vivo, we have also analyzed binding of copper (II) ions to mPrP(23-231) by EPR spectroscopy. Surprisingly, not only the unstuctured, N-terminal region PrP(23-120), but also the structured domain PrP(121-231) proved to be capable of binding copper (II) ions. This opens the possibility that copper(II) ions are involved in PrPSc formation, as the N-terminally truncated segment PrP(90-231) is sufficient for prion replication. Finally we succeeded in producing several variants of recombinant mPrP(121-231) which proved to be thermodynamically more stable than the wild type protein.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0578-1