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Mass spectroscopic analysis of Sup35NM prion polymerization
1Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA. goncharov@wi.mit.edu
Biophysical Journal
|October 4, 2005
Summary
Researchers studied the Sup35NM protein, a model for amyloid diseases, and found that the [29-98] region is crucial for its conversion into amyloid fibrils. This region forms stable dimers during the process.
Area of Science:
- Biochemistry
- Molecular Biology
- Neurodegenerative Disease Research
Background:
- The Sup35NM protein domain governs the yeast prion [Psi] and serves as a model for amyloid-related human diseases.
- Amyloid formation involves the conformational conversion of soluble proteins into insoluble fibrils.
Purpose of the Study:
- To investigate the structural changes in Sup35NM during polymerization.
- To identify key regions and residues involved in the amyloid conversion process.
Main Methods:
- Creation of Sup35NM mutants.
- Proteolytic digestion coupled with mass spectrometry to analyze protein structure.
- Comparison of experimental data with a network model.
Main Results:
- Residue Arg-28 became highly protected from cleavage during conformational conversion.
- Residue Arg-98 remained partially solvent-exposed, with intermediate protection for residues 28-98.
- A subset of proteolytic polypeptides spanning residues 28-98 spontaneously formed stable dimers.
Conclusions:
- The [29-98] region of Sup35NM is identified as the key interacting region responsible for amyloid conversion.
- The formation of stable dimers within the [29-98] segment suggests its critical role in the polymerization process.