Expression of the Fusion Protein Human Serum Album/Mutant Human Interleukin 2C125A in Pichia pastoris

Abstract:

The aim of this study was to obtain the fusion protein HSA-IL2m with high IL2 bioactivity,for this,the recombinant plasmid encoding HSA-IL2C125A was constructed and expressed in Pichia pastoris GS115.The DNA fragment encoding mutant IL-2 of C125A was design and synthesized based on codon usage bias of P.pastoris.The fragment was spliced with Human Serum Album encoding gene and then the fusion gene was cloned into pPIC9K to construct the expression plasmid pPHIm by restrictive digestion and ligation.Recombinant yeast of P.pastoris GS115/pPHIm was obtained with pPHIm linearization and electroporation.The excreting product was obtained under shake flask culture.Results: Western-blot showed the fusion protein reactive positively with the antibody of IL-2 and HSA,respectively.The crude fusion protein prepared by desalting and freeze-drying showed IL-2 bioactivity of 5.0 105 IU/mg.The results demonstrated that the fusion protein of HSA-IL2m with IL-2 bioactivity was successfully expressed in P.pastoris GS115.