Protein Expression Prokaryotic cells - B. subtilis β-CGTase

Protein expression refers to the techniques in which a protein of interest is synthesized, modified or regulated in cells. The blueprints for proteins are stored in DNA which is then transcribed to produce messenger RNA (mRNA). mRNA is then translated into protein. In prokaryotes, this process of mRNA translation occurs simultaneously with mRNA transcription. In eukaryotes, these two processes occur at separate times and in separate cellular regions (transcription in nucleus and translation in the cytoplasm). Recombinant protein expression utilizes cellular machinery to generate proteins, instead of chemical synthesis of proteins as it is very complex. Proteins produced from such DNA templates are called recombinant proteins and DNA templates are simple to construct. Recombinant protein expression involves transfecting cells with a DNA vector that contains the template. The cultured cells can then transcribe and translate the desired protein. The cells can be lysed to extract the expressed protein for subsequent purification. Both prokaryotic and eukaryotic protein expression systems are widely used. The selection of the system depends on the type of protein, the requirements for functional activity and the desired yield. These expression systems include mammalian, insect, yeast, bacterial, algal and cell-free. Each of these has pros and cons. Mammalian expression systems can be used for transient or stable expression, with ultra high-yield protein expression. However, high yields are only possible in suspension cultures and more demanding culture conditions. Insect cultures are the same as mammalian, except that they can be used as both static and suspension cultures. These cultures also have demanding culture conditions and may also be time-consuming. Yeast cultures can produce eukaryotic proteins and are scalable, with minimum culture requirements. Yeast cultures may require growth culture optimization. Bacterial cultures are simple, scalable and low cost, but these may require protein-specific optimization and are not suitable for all mammalian proteins. Algal cultures are optimized for robust selection and expression, but these are less developed than other host platforms. Cell-free systems are open, free of any unnatural compounds, fast and simple. This system is, however, not optimal for scaling up.

Start discussion

No discussions found

Share your thoughts or question with experts in your field

Start a discussion

Found 1 matching solution for this experiment

pHYαCGT1

Jing Wu, State Key Laboratory of Food Science and Technology, Ji

Upstream tips	Protocol tips	Downstream tips
For routine plasmid construction, E. coli JM109 was incubated in LB medium supplemented with 100 mg/L ampicillin for 10 h at 37 °C with shaking at 200 rpm.	To express β-CGTase in shake-flask fermentations, B. subtilis CCTCC M 2016536 plasmid strains transformed with the appropriate plasmids were incubated in 10 mL of LB medium supplemented with 20 mg/L tetracycline for 10 h at 37 °C with shaking at 200 rpm. A portion (2.5 mL; 5% [v/v]) of this overnight culture was used to inoculate 50 mL of TB medium containing 20 mg/L tetracycline, which was then incubated for 48 h at 30 °C with shaking at 200 rpm.	The culture was harvested by centrifugation at 12,000×g for 10 min at 4 °C to obtain the culture supernatant, which contained reporter proteins.

Upstream tips
For routine plasmid construction, E. coli JM109 was incubated in LB medium supplemented with 100 mg/L ampicillin for 10 h at 37 °C with shaking at 200 rpm.
Protocol tips
To express β-CGTase in shake-flask fermentations, B. subtilis CCTCC M 2016536 plasmid strains transformed with the appropriate plasmids were incubated in 10 mL of LB medium supplemented with 20 mg/L tetracycline for 10 h at 37 °C with shaking at 200 rpm. A portion (2.5 mL; 5% [v/v]) of this overnight culture was used to inoculate 50 mL of TB medium containing 20 mg/L tetracycline, which was then incubated for 48 h at 30 °C with shaking at 200 rpm.
Downstream tips
The culture was harvested by centrifugation at 12,000×g for 10 min at 4 °C to obtain the culture supernatant, which contained reporter proteins.

Publication protocol 1 Relevant paper

Can't find the product you've used to perform this experiment? It would be great if you can help us by Adding a product!

Fill out your contact details and receive price quotes in your Inbox