Expression of soluble human interleukin-2 receptor α-chain inescherichia coli

A soluble, biologically active form of IL-2Rα known as ΔMST and consisting of the 178 N-terminal amino acid residues of the mature protein was directly expressed in the cytoplasm and the periplasm ofEscherichia coli.Because it was not glycosylated, theE. coliprotein was substantially less heterogeneous than ΔMST expressed in insect cells. Nevertheless, it manifested equivalent biological activity in an IL-2 binding assay. The level of active ΔMST production was higher when the protein was expressed in secretable form with a bacterial signal peptide than when it was produced in the cytoplasm, probably because the oxidizing environment and the presence of disulfide isomerases in the periplasm facilitated the correct folding of ΔMST.