Refolding of Lysozyme in Glycerol as Studied by Fast Scanning Calorimetry.

Alisa Fatkhutdinova,Christoph Schick,Timur Mukhametzyanov

doi:10.3390/ijms23052773

Alisa Fatkhutdinova, Christoph Schick + Show 1 more

Open Access

https://doi.org/10.3390/ijms23052773

Copy DOI

Abstract

The folding of lysozyme in glycerol was monitored by the fast scanning calorimetry technique. Application of a temperature–time profile with an isothermal segment for refolding allowed assessment of the state of the non-equilibrium protein ensemble and gave information on the kinetics of folding. We found that the non-equilibrium protein ensemble mainly contains a mixture of unfolded and folded protein forms and partially folded intermediates, and enthalpic barriers control the kinetics of the process. Lysozyme folding in glycerol follows the same or similar triangular mechanism described in the literature for folding in water. The unfolding enthalpy of the intermediate must be no lower than 70% of the folded form, while the activation barrier for the unfolding of the intermediate (ca. 140 kJ/mol) is about 100 kJ/mol lower than that of the folded form (ca. 240–260 kJ/mol).

Highlights

Seventy years since the first studies [1], protein folding is still one of the central topics of biophysics [2]
We found that the non-equilibrium protein ensemble mainly contains a mixture of unfolded and folded protein forms and partially folded intermediates, and enthalpic barriers control the kinetics of the process
We have studied the folding of lysozyme in glycerol using fast scanning calorimetry

Summary

Introduction

Seventy years since the first studies [1], protein folding is still one of the central topics of biophysics [2]. The term “the protein-folding problem” covers a broad range of questions, which can be broadly grouped into three key areas [3]: (a) study of the physical forces which encode the protein 3D structure, (b) revealing the reasons for the incredibly high folding rate, and (c) predicting the structure of the protein from the amino acid sequence. In the latter area, tremendous progress has been made in recent years. The large size of protein molecules restricts the application of computational techniques to model the folding process [7]

Methods

Results

Discussion

Conclusion