Escherichia coli is the most widely used heterologous protein expression system. However, this system remains a challenge due to the low solubility of proteins, insufficient yield, and inclusion body formation. Numerous approaches have sought to address these issues. The use of a fusion tag is one of the most powerful strategies for obtaining large amounts of heterologous protein in E. coli expression system. Here, recent advances in fusion tags that increase the expression of proteins are reviewed. In addition, proposed concepts for designing peptide tags to increase protein expression are discussed.
Keywords: Aggregation-prone tag; Escherichia coli; Expression-enhancing tag; Fusion tag; Heterologous protein expression; Inclusion body; Peptide tag; Protein tag; Solubility tag.