N-terminal SKIK peptide tag markedly improves expression of difficult-to-express proteins in Escherichia coli and Saccharomyces cerevisiae

A Fab fragment bearing a leucine zipper pair at the C-termini of both heavy and light chains, named Zipbody, enhances chain pairing in the active form in E. coli cytoplasm expression and in cell-free protein synthesis systems.

“They also described an ad hoc engineered Fab fragment bearing a leucine zipper (LZ) pair at the C-termini of both the heavy and light chains, a construct named Zipbody. These extensions would enhance the chain pairing in the active form in both the E. coli cytoplasm expression and in the cell-free protein synthesis systems, a technology named Ecobody [124,125,126].”

The SKIK sequence (serine-lysine-isoleucine-lysine) improves the cytoplasmic expression of Fab fragments in the E. coli SHuffle T7 Express strain using LB medium at 16 °C for 24 h.

“Recently, the research group of Nakano has reported the use of a small tag, referred as the SKIK sequence (serine-lysine-isoleucine-lysine), that is able to improve the cytoplasmic expression of Fab fragments in the E. coli SHuffle T7 Express strain using the LB medium at 16 °C for 24 h [124,125].”

The Zipbody and SKIK peptide tag technologies have been developed to improve de novo synthesis of soluble and functional Fab fragments.

“The Zipbody and the SKIK peptide tag technologies have been developed to improve the de novo synthesis of soluble and functional Fab fragments [124,126].”