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Insulin forms amyloid in a strain-dependent manner: an FT-IR spectroscopic study
Wojciech Dzwolak1, Vytautas Smirnovas, Ralf Jansen
1High Pressure Research Center, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland. wdzwolak@unipress.waw.pl
Summary
Ethanol induces distinct insulin amyloid structures that mimic prion strains. The initial amyloid seed dictates the final structure, overriding environmental influences, suggesting amyloid strains are common.
Area of Science:
- Biochemistry
- Structural Biology
- Biophysics
Background:
- Amyloid fibrils are associated with various diseases.
- Understanding amyloid formation and propagation is crucial for therapeutic development.
- Prion-like behavior in protein aggregation suggests a mechanism for disease transmission.
Purpose of the Study:
- To investigate the structural characteristics of insulin amyloid formed under different conditions.
- To determine if insulin amyloid exhibits prion strain-like properties.
- To explore the influence of seeding on amyloid structure and stability.
Main Methods:
- Induction of insulin amyloid formation using 20% ethanol.
- Comparison of amyloid structures using infrared spectroscopy.
- Analysis of seeding specificity and conformational templating.
Main Results:
- Ethanol-induced insulin amyloid exhibits distinct infrared spectroscopic features compared to ambient conditions.
- Both insulin amyloid types demonstrate prion strain-like behavior in seeding specificity.
- The initial seed's conformation dictates the amyloid structure, overriding environmental factors like cosolvents.
- This conformational templating influences spectral properties such as amide I' band position and width.
Conclusions:
- Insulin amyloid can exist in distinct structural forms, analogous to prion strains.
- The self-propagating nature of amyloid conformation suggests a general mechanism for amyloid diversity.
- These findings imply that "strains" may be a common characteristic of amyloidogenic proteins.