RESUMEN
The chicken-type lysozyme of the insect Spodoptera litura (SLLyz) is a polypeptide of 121 amino acids containing four disulfide bridges and 17 rare codons and participates in innate defense as an anti-bacterial enzyme. The recombinant S. litura lysozyme (rSLLyz) expressed as a C-terminal fusion protein with glutathione S-transferase (GST) in Rosetta(DE3) Singles. The protein was produced as an inclusion body which was solubilized in 8 M urea, renatured by on-column refolding, and purified by reversed-phase chromatography to 95 percent purity. The purified rSLLyz demonstrated antibacterial activity against B. megaterium confirmed by inhibition zone assay. The overexpression and refolding strategy described in this study will provide a reliable technique for maximizing production and purification of proteins expressed as inclusion bodies in E. coli.
Asunto(s)
Cuerpos de Inclusión/metabolismo , Muramidasa/metabolismo , Spodoptera , Antibacterianos , Bacillus megaterium , Western Blotting , Cromatografía de Fase Inversa , Electroforesis , Escherichia coli , Glutatión Transferasa , Pliegue de Proteína , Proteínas RecombinantesRESUMEN
EC-SOD inclusion bodies was refolded on column using metal (Ni) affinity chromatography, based on the metal-binding property of His-tag. The effect of protein amount, urea removal speed and temperature on refolding was observed. We compared the different efficiency purified with Ni-sepharose and Heprain-sepharose affinity chromatography, and studied the stability of the refolded proteins. The results indicate that the inclusion bodies can be renatured with Ni-sepharose affinity chromatography. The increase of the protein amount and urea removal rate , the lower of the renaturation efficiency. Higher temperature was benefit to protein renaturation. Both the Ni-sepharose and Heprain-sepharose affinity column can be used to purified the refolded proteins, but purified by Heprain-sepharose affinity column the protein had higher activity. The activity of renatured protein was stable in 10 ℃～50℃,when pH10 its stability was lower significantly. In denaturating solution the stability of renatured protein was low.