Construction, expression and purification of recombinant Slp. A: Amplification of slp gene by PCR; B: Double digestion analysis of recombinant plasmid; C: Expression and purification of Slp. M1: DNA Marker; M2: Protein Marker. 1: slp gene by PCR; 2: Recombinant plasmid of slp; 3: Double digestion by EcoR Ι and Xho I; 4: Uninduced strain; 5: IPTG induced strain; 6: Purified Slp protein. The results showed that slp recombinant plasmid was constructed, and the Slp protein was expressed and purified successfully.