Secretion Expression of Mt. Heat Shock Protein 70 in Pichia pastoris and Identification of the Protein
结核杆菌热休克蛋白70在毕赤酵母中的分泌表达与鉴定

To obtain the expression of Mycobacterium tuberculosis heat shock protein 70 in methylotropic yeast. The expression vector pPIC9K-hsp70 was constructed, linearized and introduced into Pichia pastoris GS115 by electroporation. The result protein was secreted into the supernatant induced by 0.5% methanol at 30 degrees C and purified by centrifugation, ultrafiltration and ATP-agarose. The recombinant Hsp70 was identified by SDS-PAGE, Western blot, mice experiment and effect on the immature DC. The SDS-PAGE and Western blot analysis showed that the apparent molecular weight of expressed Hsp70 was about 70 kD and the expressed protein could specifically react with anti-Mt. Hsp70 IgG. And mice immunization indicated the expressed hsp70 had immunogenicity. Hsp70 could induce DC maturation and release Th1 cytokine. The secreted 70 kD protein was about 120 mg/L which accounted for more than 30% of the total supernatant protein and was purified to electrophoretic purity. The Hsp70, which had the biological activity, is successfully secretorily expressed in the Pichia pastoris GS115.