Prokaryotic Expression, Purification And Immunoactivity Analysis Of Fusion Protein Of Melittin And Human Mutant Interleukin-2

Objective To modify the IL-2 gene by changing the 88 asparagine condon to arginine condon and express recombinant melittin-human mutant inteleukin-2 fusion protein in Escherichia coli. The fusion protein was also purified and detected its immunoactivity. Methods The gene encoding human interleukin-2 has been cloned from PHA-induced human tonsil cell. Site-specific mutagenesis procedures were used to modify the IL-2 gene by changing the 88 asparagine condon to arginine condon. Nucleotide sequence analysis of the gene revealed correct result. A fusion protein of melittin and mutant IL-2 were connected to each other by a linker peptide (Gly4Ser)3 . Expression plasmids containing the melittin and mutant IL-2 cDNA were transformed into Ecoli DH5 a . The expressed products were purified by affinity chromatography using GST Fusion Protein Purification bead. And its immunoactivity was analyzed using Western blotting analysis. Results The recombinant vectors containing mutated IL-2 gene and fusion protein cDNA were obtained. The purity of the purified protein was about 90%. Western blotting test revealed that it had good specificity to monoclonal antibodies of anti-IL-2. Conclusion The fusion protein was expressed in prokaryotic system. It may be a new drug in the clinic to regulate the immunological function.