Co-refolding denatured-reduced hen egg white lysozyme with acidic and basic proteins

Area of Science:

• Biochemistry
• Protein Folding
• Biophysics

Background:

• Protein misfolding and aggregation are critical issues in biotechnology and disease.
• Understanding protein refolding is essential for protein production and therapeutic applications.
• Lysozyme is a model protein frequently used to study refolding dynamics.

Purpose of the Study:

• To investigate the impact of co-refolding lysozyme with various proteins on its renaturation yield and aggregation.
• To elucidate the role of protein charge and hetero-interchain interactions in protein refolding.
• To identify conditions that optimize lysozyme refolding and minimize aggregation.

Main Methods:

• Denatured-reduced lysozyme was refolded.
• Co-refolding experiments were performed with RNase A, bovine serum albumin, histone, myelin basic protein, alcohol dehydrogenase, and DNase I.
• Renaturation yields and aggregation levels were quantified.

Main Results:

• Co-refolding with basic proteins (histone, myelin basic protein) increased lysozyme renaturation yield by 10-20% with minimal aggregation.
• Co-refolding with acidic proteins (bovine serum albumin, alcohol dehydrogenase, DNase I) led to significant aggregation and decreased renaturation yields.
• Evidence of hetero-interchain interactions between lysozyme and acidic proteins was observed.

Conclusions:

• The net charge of co-refolded proteins significantly influences lysozyme aggregation and renaturation.
• Basic proteins promote lysozyme refolding, while acidic proteins induce non-specific aggregation.
• These findings offer insights into protein-protein interactions during the refolding process.