Structural hot spots for the solubility of globular proteins

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Engineering

Background:

• Natural protein sequences are shaped by evolution for specific physiological requirements, often resulting in limited solubility at high concentrations.
• Recombinant protein production frequently faces challenges due to insufficient protein solubility, hindering biotechnological and therapeutic applications.

Purpose of the Study:

• To investigate whether the solubility of natural protein sequences can be improved by targeting aggregation-prone regions (APRs).
• To identify specific mutation sites ('hot spots') that enhance protein solubility without affecting protein stability or function.

Main Methods:

• Computational prediction of aggregation-prone regions (APRs) within protein sequences.
• Site-directed mutagenesis to suppress identified APRs.
• Assessment of protein solubility and stability changes post-mutation.
• Experimental validation using human α-galactosidase and Bacillus anthracis protective antigen.

Main Results:

• An inverse correlation was observed between the number of aggregation-prone regions (APRs) in a protein sequence and its overall solubility.
• Specific mutations within protein structures were identified as effective APR suppressors, increasing solubility without compromising protein stability.
• Computationally predicted 'hot spots' for solubility enhancement were validated experimentally.
• Reduced aggregation was achieved for human α-galactosidase and Bacillus anthracis protective antigen through targeted mutagenesis.

Conclusions:

• Mutational suppression of aggregation-prone regions (APRs) is a viable strategy to enhance protein solubility.
• Protein solubility can be modulated independently of protein structure and function by targeting specific 'hot spots'.
• This approach offers a powerful tool for improving protein engineering and recombinant protein production.