De novo design of cysteine proteases.

De novo designed cysteine proteases achieve up to 3 × 10^7 rate enhancement with 19% success rate in hydrolyzing peptide bonds in mammalian cells.

• Why it matters: Peptide bonds are highly stable in neutral aqueous solutions, making their enzymatic hydrolysis challenging, and current enzyme design methods have limited success beyond simple reactions, creating a need for more effective synthetic proteases.
• What they did: The authors used a de novo design approach to create enzymes with activated cysteine nucleophiles, resulting in six crystal structures closely matching their models and a success rate of 13 out of 69 designs.
• The result: These designed proteases can efficiently cleave targets in mammalian cells, demonstrating potential for broad applications in synthetic biology and highlighting the accuracy and generalizability of the design methodology.