Folding of Prion Protein to Its Native α-Helical Conformation Is under Kinetic Control

Ilia V Baskakov,Giuseppe Legname,Stanley B Prusiner,Fred E Cohen

doi:10.1074/jbc.c100180200

Ilia V Baskakov, Giuseppe Legname + Show 2 more

Open Access

https://doi.org/10.1074/jbc.c100180200

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Abstract

The recombinant mouse prion protein (MoPrP) can be folded either to a monomeric alpha-helical or oligomeric beta-sheet-rich isoform. By using circular dichroism spectroscopy and size-exclusion chromatography, we show that the beta-rich isoform of MoPrP is thermodynamically more stable than the native alpha-helical isoform. The conformational transition from the alpha-helical to beta-rich isoform is separated by a large energetic barrier that is associated with unfolding and with a higher order kinetic process related to oligomerization. Under partially denaturing acidic conditions, MoPrP avoids the kinetic trap posed by the alpha-helical isoform and folds directly to the thermodynamically more stable beta-rich isoform. Our data demonstrate that the folding of the prion protein to its native alpha-helical monomeric conformation is under kinetic control.

Highlights

From the ‡Institute for Neurodegenerative Diseases and Departments of §Neurology, ¶Biochemistry and Biophysics, and ʈCellular and Molecular Pharmacology, Pharmaceutical Chemistry, and Medicine, University of California, San Francisco, California 94143
By using circular dichroism spectroscopy and size-exclusion chromatography, we show that the ␤-rich isoform of mouse prion protein (MoPrP) is thermodynamically more stable than the native ␣-helical isoform
The conformational transition from the ␣-helical to ␤-rich isoform is separated by a large energetic barrier that is associated with unfolding and with a higher order kinetic process related to oligomerization

Summary

Introduction

From the ‡Institute for Neurodegenerative Diseases and Departments of §Neurology, ¶Biochemistry and Biophysics, and ʈCellular and Molecular Pharmacology, Pharmaceutical Chemistry, and Medicine, University of California, San Francisco, California 94143. The recombinant mouse prion protein (MoPrP) can be folded either to a monomeric ␣-helical or oligomeric ␤-sheet-rich isoform. The conformational transition from the ␣-helical to ␤-rich isoform is separated by a large energetic barrier that is associated with unfolding and with a higher order kinetic process related to oligomerization.

Results

Conclusion