The scientists studied how a viral protease evolved over time in the lab to understand enzyme engineering better. They changed a key part of the protease and saw a big drop in its activity, but through directed evolution, they made it work again. By letting neutral mutations accumulate, they found that some enzymes became more robust and better at handling mutations. They also discovered that these enzymes could adapt to new tasks more easily. Overall, the research shows how understanding evolution can help improve enzymes for various purposes.