RESUMEN
Recombinant human interleukin-1 receptor antagonist was expressed in E. coli as an insoluble inclusion body. The inclusion body was dissolved in the 8 M urea and then the solution was diluted untill the concentration of urea became 2 M. By ion exchange chromatography the protein in the solution of 2 M urea was refolded and purified. At last the purity of product is more than 95% and its bioactivity is more than 1 x 10(5) IU/mg while it has little endotoxin. Western-Blotting also indicates that recombinant protein can react with antibodies against anti-hIL-1ra.
Asunto(s)
Cuerpos de Inclusión/metabolismo , Proteína Antagonista del Receptor de Interleucina 1/biosíntesis , Pliegue de Proteína , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Proteína Antagonista del Receptor de Interleucina 1/genética , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificaciónRESUMEN
Recombinant human interleukin-1 receptor antagonist (rHuIL-1ra) was produced in E. coli as an inclusion body. rHuIL-1ra was purified to Over 98% purity by anion exchange chromatography after on-column refolding. The optimized processes produced more than 2 g pure refolded rHuIL-1ra per 1 l culture, corresponding to a 44% recovery, without an intermediate dialysis step. Refolded rHuIL-1ra had full biological activity with the MTT assay. An intramolecular disulfide linkage in the oxidized recombinant protein was suggested by data from HPLC and non-reducing SDS-PAGE.
Asunto(s)
Cromatografía por Intercambio Iónico/métodos , Escherichia coli/genética , Escherichia coli/metabolismo , Cuerpos de Inclusión/metabolismo , Ingeniería de Proteínas/métodos , Sialoglicoproteínas/biosíntesis , Sialoglicoproteínas/aislamiento & purificación , Humanos , Cuerpos de Inclusión/química , Proteína Antagonista del Receptor de Interleucina 1 , Pliegue de Proteína , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Sialoglicoproteínas/genéticaRESUMEN
Mature human interleukin-11 (HuIL-11) is a cytokine consisting of 178 amino acid residues that results from scission of the N-terminal signal peptide, consisting of 21 amino acid residaues, from the corresponding nascent polypeptide. A DNA fragment encoding a truncated HuIL-11 (trHuIL-11), with an additional 5 amino acid residues removed from the N-terminus, was cloned into vector pGEX-2T between the BamHI site and the EcoRI site. Upon transformation with Escherichia coli BL21, the construct over-produced a glutathione S-transferase (GST)-fused protein in a soluble form after IPTG induction. The fusion protein was initially fractionated with butyl-Sepharose 4 fast flow column and by affinity chromatography using a GSH-Sepharose 4B column. On-site enzymatic release with thrombin gave the target protein at 96% purity as judged by SDS-PAGE and HPLC. Expression of the interleukin as a GST-fused protein thus greatly improved downstream processing. Subsequent biological activity assay suggested that trHuIL-11 had similar activity profile to the naturally produced sample and may be a promising candidate for further development as biopharmaceutical.