Aggregation characteristics of ovalbumin in beta-sheet conformation determined by spectroscopy.
Protein misfolding and aggregation are involved in a number of the so-called "conformational" diseases (e.g., transmissible spongiform encephalopathies and Alzheimer disease). The development of rational strategies to interfere with aggregation is a potential therapeutic approach that requires complete knowledge of the aggregation process. We studied the aggregation of ovalbumin in beta-sheet conformation using mainly the spectral changes in the spectra of two dyes (Congo Red and pinacyanol) caused by the aggregates. We assumed a linear model of polymerization that fit to the experimental data. The critical aggregation constant, concentration of half-aggregation, nucleation parameter, growth parameter, and number of aggregation and free energy changes (total and per residue) were determined as aggregation-related parameters. Beta-Ovalbumin aggregates in a cooperative way. Moreover, the differences between such parameters obtained with Congo Red and pinacyanol suggest that each dye interacts with the protein in its own way.
Sabaté
Raimon
R
Departament de Fisicoquímica, Universitat de Barcelona, Catalonia, Spain. estelric@farmacia.far.ub.es
Estelrich
Joan
J
D010047:Ovalbumin / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
D010047:Ovalbumin