Question

You are trying to design a protein that will be expressed in Escherichia coli and secreted outside of the cell for purification and use as a pharmaceutical. E,coli is a gram-negative cell and the protein folds after it has existed the cell. Which secretion system would work best for this project? Support your answer with evidence based on the properties of E.coli, the protein , and the secretion system.

Answer 1

Given :

• Protein - should be expressed in Escherichia coli , should be secreted outside of the cell for purification , should be used as a pharmaceutical
• E.coli - Gram negative cell , proteins folds after it has existed the cell

Secretion system that works best is -

SEC AND TAT PATHWAY

• It is a two step secretion system
• In this system , the protein is produced that moves to the periplasm and then outside the cell
• Here, the protein folds - after itit has existed the cell
• Among both , the TAT system works best . This is because , it secretes the already folded proteins
• Whereas in SEC system , it secretes unfolded proteins