Co-expression of recombinant single chain variable fragment recognizing blood antigen fused with sumo and chaperones in Escherichia coli

Abstract

Single chain variable fragments (scFv) have widely been used in research, diagnosis and treatment, but the scFv is considered as difficult protein for expression in Escherichia coli (E. coli). In previous studies, we expressed a construction of recombinant single chain variable fragments again antigen specific for blood type A (antiA-scFv) individually or fused with Trx or SUMO. However, soluble fraction was low abandant and only approximately 40% when fused with Trx, the other cases were expressed in form of inclusion body. Therefore, it was difficult for purification, refolding and activity assessment. In this paper, we demonstrated a suitable construction for soluble production of antiA-scFv fused with SUMO (SUMO/antiA-scFv) in presence of chaparones. Under fermentation with 0.1 mM IPTG at 20oC, the SUMO/antiA-scFv was entirely expressed in soluble form. Importantly, after cleavage from SUMO with SUMO protease, antiA-scFv was still maintained in the supernatant fraction. Therefore, it can help ensure bioactivity and is useful for purification process. To the best of our knowledge, this is the first report showing soluble recombinant scFv fused with SUMO in presence of chaperone for determination of blood group antigens. Thus, this result facilitates the optimal study of soluble expression, purification and bioactivity determination of the antiA- scFv recombinant antibody.