The optimization of growth conditions for specific client proteins

Features
• Multiple customer defined optimization parameters
• Scaleable, high-throughput assay development
• High precision with low assay variation
• Fast turnaround time
• Complete analysis with optimized conditions

Protein expression in bacterial systems can be affected by the chemical and physical conditions of the culture environment. Testing multiple culture conditions can improve methods for controlling bacterial activities such as protein expression and gene function.

Culture conditions commonly considered for optimization of E. coli growth include, but are not limited to, temperature, pH, oxygen, and nutrition. However, high levels of induced protein expression in E. coli could be detrimental to cell growth and viability. Therefore, expression systems with controllable promoters, such as pBAD, pT7, pLac, pTac, pTrc, pL, and pR, and their respective inducers have been widely used to modulate the production of the cloned gene products at substantially high levels without causing toxic effects to the cells.

The OPTI-Grow system screens multiple E. coli growth condition variables using deep-well culture plates to find conditions that provide maximized protein expression of the target gene(s) of interest. Systematic, automated optimization of growth includes variable inducer concentrations, induction times, and temperatures. Upon request, additional parameters such as host strain selection, cell density, and other customized variables can be included for optimization.

Figure 1:  Effects of growth time after induction with arabinose on the expression of protein X (the expected molecular weight as indicated by the arrow) under control of the pBAD promoter. Lane M: molecular markers (in kDa); Lane 1-4: induced with 0, 0.0002, 0.002, and 0.02% arabinose at 37°C for 1 hr; Lane 5-8 induced with 0, 0.0002, 0.002, and 0.02% arabinose at 37°C for 2 hrs; Lane 9-12: induced with 0, 0.0002, 0.002, and 0.02% arabinose at 37°C for 4 hrs.

Figure 2:  Effects of arabinose concentrations on the induced expression of protein X (the expected molecular weight as indicated by the arrow) under control of the pBAD promoter. Lane M: molecular weight markers (in kDa); Lane 1-6: induced with 0, 0.00002, 0.0002, 0.002, 0.02 and 0.2% arabinose at 37 oC.