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Affinity-tagged miniprion derivatives spontaneously adopt protease-resistant conformations
S Supattapone1, H O Nguyen, T Muramoto
1Institute for Neurodegenerative Diseases, University of California at San Francisco, San Francisco, California 94143, USA.
Journal of Virology
|November 23, 2000
Summary
Researchers engineered prion proteins (PrP106) with affinity tags, creating novel miniprions that spontaneously adopt protease-resistant forms. These engineered PrP proteins may aid in identifying new disease mutations and screening therapeutic compounds.
Area of Science:
- Biochemistry
- Neuroscience
- Prion Biology
Background:
- Prion protein (PrP) misfolding is central to neurodegenerative diseases.
- Miniprions, truncated PrP forms, can be infectious in vivo.
- Engineered PrP variants offer tools to study misfolding pathways.
Purpose of the Study:
- To investigate if affinity tags on truncated PrP (PrP106) induce spontaneous protease resistance.
- To determine how tag characteristics and mutations influence PrP misfolding.
- To assess the potential of these engineered PrP forms as research tools.
Main Methods:
- Expression of abridged PrP (PrP106) with various six-histidine (His(6)) affinity tags in neuroblastoma cells and transgenic mice.
- Assessment of protease resistance of engineered PrP variants.
- Introduction of disease-associated mutations (E200K, C213A, Delta214-220) into PrP sequences.
- Treatment with polypropyleneimine dendrimer to assess protease sensitivity.
Main Results:
- Certain His(6) tagged PrP106 variants spontaneously acquired protease resistance.
- Protease resistance acquisition was dependent on tag length, charge, and placement.
- The E200K mutation significantly increased protease-resistant PrP recovery.
- Polypropyleneimine dendrimer treatment restored protease sensitivity to tagged PrP mutants.
Conclusions:
- Engineered PrP106 proteins with specific affinity tags can spontaneously fold into protease-resistant conformations.
- These conformations partially mimic, but are distinct from, wild-type PrP(Sc).
- These novel PrP constructs serve as valuable tools for prion disease research, mutation identification, and drug screening.