Thesis presented December 09, 2004

Abstract:
Protein folding is one of the central problems in biology. Denaturation and folding of the proteins with more than 100 amino acids is not cooperative and goes through the accumulation of stable intermediates. Structural characterization of such intermediates is essential for better understanding of protein folding reaction and possible deviations that can lead to the development of severe diseases.
The folding and denaturation mechanisms have been studied for two model proteins α-lactalbumin and carbonic anhydrase B. Several intermediates have been discovered during the equilibrium denaturation of carbonic anhydrase in different denaturizing​ conditions. These intermediates differ by their capability to aggregate and associate. In the case of α-lactalbumin, metal effects on the refolding kinetics have been characterized in detail. Thermodynamic aspects of metal binding to different intermediate states of the α-lactalbumin are discussed. Then, nuclear magnetic resonance and infrared spectroscopy were associated for study the secondary and tertiary structure changes that occur during the folding reaction of α​-lactalbumin. A method of correlation spectroscopy has been used to compare the observations done by the two types of spectroscopy and for a very detailed description of all the structural changes implied in the reaction.

Keywords:
protein​ folding, denaturation, molten globule, carbonic anhydrase, α-lactalbumin

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