Efficient Soluble Expression,Purification and Activity of Murine Ribonuclease Inhibitor

The paper was to obtain efficient soluble expression of mouse ribonuclease inhibitor(MRNI). By constructing a recombinant expression vector containing SUMO,IF2,GST,NusA,MsyB,Trx and MBP fusion tags,E. coli BL21(DE3)was used as a host strain for auto-induction(AI)expression,and MagNi magnetic beads were used for detection. The expression of MRNI was analyzed by electrophoresis,and the culture temperature and time were optimized. The results showed that the soluble fusion protein IF2-MRNI induced by recombinant BL21(DE3)(pNBEⅡ-MRNI)had the highest yield,and the optimal induction condition was 37 ℃,induced for 6 h,and cultured at 20 ℃ for 24 h. The concentration of the fusion protein IF2-MRNI obtained after purification of the magnetic beads was 3621.3 mg/L. Compared with RI activity of other companies,the enzyme activity was about 40 U/μL. The enzyme had the function of inhibiting RNase A activity and preventing degradation of RNA,and provided a theoretical basis for the production and application of RI.