A Desolvation Model for Trifluoroethanol-Induced Aggregation of Enhanced Green Fluorescent Protein
| Autor: | Watt W. Webb, Valerie L. Anderson |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Circular dichroism
Amyloid Green Fluorescent Proteins 030303 biophysics Population Biophysics Protein aggregation Protein Structure Secondary Green fluorescent protein 03 medical and health sciences chemistry.chemical_compound Animals Intermediate state education 030304 developmental biology 0303 health sciences education.field_of_study Protein Trifluoroethanol Hydrogen-Ion Concentration Protein tertiary structure Protein Structure Tertiary Crystallography Hydrozoa Spectrometry Fluorescence Monomer chemistry Solvents Thermodynamics Protein Multimerization |
| Zdroj: | Biophysical Journal. 102:897-906 |
| ISSN: | 0006-3495 |
| Popis: | Studies of amyloid disease-associated proteins in aqueous solutions containing 2,2,2-trifluoroethanol (TFE) have shown that the formation of structural intermediates is often correlated with enhanced protein aggregation. Here, enhanced green fluorescent protein (EGFP) is used as a model protein system to investigate the causal relationship between TFE-induced structural transitions and aggregation. Using circular dichroism spectroscopy, light scattering measurements, and transmission electron microscopy imaging, we demonstrate that population of a partially α-helical, monomeric intermediate is roughly correlated with the growth of β-sheet-rich, flexible fibrils for acid-denatured EGFP. By fitting our circular dichroism data to a model in which TFE-water mixtures are assumed to be ideal solutions, we show that increasing entropic costs of protein solvation in TFE-water mixtures may both cause the population of the intermediate state and increase aggregate production. Tertiary structure and electrostatic repulsion also impede aggregation. We conclude that initiation of EGFP aggregation in TFE likely involves overcoming of multiple protective factors, rather than stabilization of aggregation-prone structural elements. |
| Databáze: | OpenAIRE |
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