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Human stefin B readily forms amyloid fibrils in vitro
Eva Zerovnik1, Marusa Pompe-Novak, Miha Skarabot
1Department of Biochemistry and Molecular Biology, Institute Jozef Stefan, Jamova 39, 1000 Ljubljana, Slovenia. eva.zerovnik@ijs.si
Biochimica Et Biophysica Acta
|February 5, 2002
Summary
Human stefin B (cystatin B), an intracellular proteinase inhibitor, readily forms amyloid fibrils in vitro. This discovery offers a new model for studying protein misfolding and fibrillogenesis.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Human stefin B (cystatin B) is an intracellular cysteine proteinase inhibitor found in various tissues.
- Protein aggregation and amyloid fibril formation are implicated in several neurodegenerative diseases.
Purpose of the Study:
- To investigate the in vitro fibrillogenic potential of recombinant human stefin B.
- To characterize the structural properties of human stefin B amyloid fibrils.
Main Methods:
- Recombinant human stefin B expression and purification.
- Transmission electron microscopy (TEM) and atomic force microscopy (AFM) for fibril visualization.
- Thioflavin T fluorescence assay and Congo red dye binding for amyloid characterization.
Main Results:
- Recombinant human stefin B spontaneously forms amyloid fibrils in vitro over several months.
- Fibrils exhibit regular structures with specific dimensions (14 nm diameter, 27 nm longitudinal repeats).
- Thioflavin T and Congo red assays confirm amyloid nature; trifluoroethanol accelerates fibrillation.
Conclusions:
- Human stefin B readily forms amyloid fibrils in vitro, unlike its homologue stefin A.
- This protein serves as a valuable model system for studying fibrillogenesis.
- Further in vivo studies are warranted to understand stefin B's role in health and disease.