Cloning,expression and characterization analysis of the arginine deiminase of Streptococcus suis of China isolates

Abstract:

PCR analysis demonstrated the presence of the ad gene in all 29 S.suis strains tested, but none of the seven S.equi subsp. zooepidemicus strains. The fragment of ad gene of virulent isolate SS2-HA9801 was later cloned into pBAD/Myc-HisC vector via restriction endonuclease and then transformed into host strain TOP10. A recombinant protein of 47000Da was highly expressed after induced by L-ararose and purified by Ni-nitrilotriacetic acid affinity chromatography. Western blotting demonstrated that the recombinant protein can reacted to the polyclonal antibody raised against whole-cell protein of SS2-HA9801, which suggested that it possessed some immunogenicity and may be important for further research. Enzymatic assay revealed that the optimum temperature for its activity is 37℃ and pH is 6.5. Studies with class-specific inhibitors supported the assignment of a sulfhydryl enzyme with some metallo class characteristics.

Key words:Streptococcus suis; arginine deiminase; cloning and expression; enzymatic activities