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Relationship between functional properties and structure of ovalbumin
M Zemser1, M Friedman, J Katzhendler
1Department of Pharmaceutical Chemistry, School of Pharmacy, Hebrew University of Jerusalem, Israel.
Journal of Protein Chemistry
|February 1, 1994
Summary
This study investigated ovalbumin denaturation using various chemicals. Denaturation kinetics and structural changes were analyzed, revealing reversible unfolding and altered secondary structures.
Area of Science:
- Biochemistry
- Protein Chemistry
- Structural Biology
Background:
- Ovalbumin is a model protein extensively studied for its structural properties.
- Understanding protein denaturation is crucial for various biological and industrial applications.
Purpose of the Study:
- To investigate the denaturation effects of ovalbumin (OVA) induced by a range of chemical agents.
- To characterize the kinetics and reversibility of OVA unfolding.
- To analyze the impact of denaturation on OVA's secondary and quaternary structure.
Main Methods:
- Ovalbumin denaturation using urea, guanidinium chloride, SDS, CPC, CHAPS, cationic detergents, HCl, and CH3COOH.
- Fluorescence spectroscopy to monitor protein unfolding (intensity, peak response, emission maximum).
- Circular Dichroism (CD) spectroscopy to assess secondary structure changes.
- Polyacrylamide Gel Electrophoresis (PAGE) and SDS-PAGE to analyze subunit structure and aggregation.
Main Results:
- Denaturation kinetics often followed a double exponential decay, with exceptions at low urea/acid concentrations indicating first-order reactions.
- Reversible unfolding-folding transitions were confirmed via fluorescence and CD.
- Significant alterations in secondary structure, including changes in alpha-helical content, were observed.
- SDS-PAGE revealed differences between native and denatured ovalbumin, with aggregated forms appearing around 45 kD.
Conclusions:
- Various chemical agents induce distinct denaturation pathways in ovalbumin.
- Ovalbumin's unfolding is largely reversible, with measurable changes in secondary and quaternary structure.
- The study provides insights into protein structural dynamics and the influence of denaturants.