The study aimed to create a version of the suilysin protein that does not cause hemolysis (destruction of red blood cells) while still retaining its immune response capabilities.
Researchers mutated the proline residue at position 353 to three different amino acids (alanine, leucine, and valine) and purified these recombinant proteins to test their hemolytic activity.
Among the mutants, SLY(P353V) exhibited no hemolytic activity but still demonstrated significant immunogenicity in further tests.