5. Conclusion
In summary, we have successful produced IL-18 mutation variants fromE. coli expression system. Although the most of protein was
expressed as inclusion body, we accomplished the refolding method
yielding the soluble form of IL-18 with activity. From all of results we
presented, the mutation of surface cysteine to serine of IL-18 DM could
reduce the aggregation prone while enhanced the activity. Despite the
deep mechanism of this scenario has not been elucidated, the possibility
may be from the structural changes that led to the more appropriate form
of IL-18 and receptor binding. The increase of active IL-18 resulted
from the lower aggregation rate may also help it activity. Further study
regarding to the mechanism of this scenario must be useful to apply for
other proteins or biologic drugs.