Enhanced production of antibody fragment via SRP pathway engineering in Escherichia coli

Abstract

In Escherichi coli, Sec-dependent pathway is the major pathway for protein secretion into periplasm, and it has been widely used for the production of antibody fragment. However, in many cases, the production yields of antibody fragments were not satisfactory due to inefficient secretion and low solubility. Here, we have developed the host-vector system for the secretory production of single chain Fv (scFv) via signal recognition particle (SRP)-dependent pathway instead of Sec-dependent pathway. Use of DsbA signal peptide for SRP-dependent pathway allowed more efficient production of scFv compared with Secdependent pathway. To further improve the production yield and solubility of scFv via SRP pathway, the effect of several factors which are closely related to SRP pathway were examined. Among those factors, the co-expression of YidC could significantly improve the solubility of scFv with high expression level. For the large-scale production, fed-batch cultivations with engineered host-vector system were performed and, two different nutrient feeding solutions (complex vs. defined) were examined. When defined feeding solution was supplied, higher production yield (90 mg/L of scFv) could be obtained than complex feeding solution.