Production of mutant streptokinase recombinant protein

Background: Streptokinase (SK) is most widely used for treatment of myocardial infarction, however, it is the most expensive thrombolytic agent. A major drawback to SK use is the widespread presence of anti–streptokinase antibodies (Abs). These Abs cause allergic reactions and neutralize streptokinase therapeutic effects. Materials and methods: To produce an engineered variant of streptokinase being functional and less antigenic than the native molecule, we cloned and expressed streptokinase mutant gene lacking the C – terminal 42 amino acids. Recombinant protein was confirmed by western blot analysis with anti T7 monoclonal antibodies. Results: pGEMEX-1 expression vector contains T7 gene 10 protein as fusion protein immediately down stream of T7 promoter and before multiple cloning site, streptokinase mutant gene was cloned after fusion protein. Conclusion: We cloned and expressed mutant streptokinase gene, lacking the C-terminal 42 amino acids. If mut-C42 activity was less affected by neutralizing antibodies compared with native streptokinase, this engineered variant could be a preferred alternative to native streptokinase for thrombolytic therapy.

Streptokinase, Myocardial infarction. Mutation, Cloning.