Stable Mammalian Serum Albumins Designed for Bacterial Expression

Area of Science:

• Biochemistry
• Protein Engineering
• Biotechnology

Background:

• Albumin, abundant in blood serum, has vital physiological and carrier functions.
• Current albumin sources (animal serum, yeast, rice) present ethical, reproducibility, or expression challenges.
• Disulfide bonds complicate heterologous albumin expression, limiting applications.

Purpose of the Study:

• To engineer highly stable and expressible albumin variants using computational design.
• To overcome limitations of current albumin production methods for research and industry.

Main Methods:

• Utilized the PROSS algorithm for computational stabilization of human and bovine serum albumins.
• Expressed engineered albumin variants in E. coli.
• Verified design accuracy through crystallographic analysis and assessed ligand binding properties.

Main Results:

• Engineered albumins demonstrated high expression levels in E. coli.
• A variant with 16 mutations retained wild-type ligand binding.
• A 73-mutation variant exhibited over 40°C increased stability, remaining functional above water's boiling point.

Conclusions:

• Proteins with multiple disulfide bonds can achieve extreme stability through protein design.
• Designed albumins offer a path to economical, reproducible, and animal-free reagents for molecular and cell biology.
• This work enables high-throughput screening to enhance albumin carrier functions.