[Construction and activities of suilysin mutants].

AIM: To construct the suilysin mutant without hemolytic activity and evaluate its functions. METHODS: The proline in 353 site of suilysin was site-directed mutated to alanine, leucine and valine, respectively. The recombinant mutants were renaturated and purified by immobilized metal ion affinity chromatography, and the purified proteins were evaluated in the hemolytic activity and immunogenicity. RESULTS: We obtained three mutants, SLY(P353A), SLY(P353L) and SLY(P353V). The SLY(P353V) mutant had non-hemolytic activity. Western blotting and animal experiments showed that SLY(P353V) mutant still had immunogenicity. CONCLUSION: Suilysin mutant SLY(P353V) has no hemolytic activity but remains immunogenicity.