A scalable screening of E. coli strains for recombinant protein expression

Area of Science:

• Structural Biology
• Protein Expression
• Molecular Biology

Background:

• Large-scale soluble protein expression is essential for structural biology.
• Heterologous expression in bacteria or yeast is commonly used.
• Optimizing protein constructs, expression conditions, and host systems are key challenges.

Purpose of the Study:

• To evaluate a scalable approach for screening host cells for protein expression.
• To identify the optimal Escherichia coli strain for maximal soluble heterologous protein yield.

Main Methods:

• Evaluated four Escherichia coli strains (pT-GroE, Lemo21(DE3), Arctic Express (DE3), Rosetta Gami 2 (DE3)) alongside a standard strain (Rosetta 2 (DE3)).
• Utilized a liquid handling robot for high-throughput screening.
• Maintained consistent protein construct and gene cloning strategies across strains.

Main Results:

• The Arctic Express (DE3) strain yielded higher amounts of soluble heterologous proteins compared to the other strains tested.
• Screening identified a superior host strain for protein expression within the tested parameters.

Conclusions:

• Screening of host cells/strains for protein expression is feasible, even for smaller laboratories.
• The proposed experimental approach is scalable to high-throughput methods.
• Arctic Express (DE3) is recommended for enhanced soluble protein yields in structural biology pipelines.