De novo design of catalytic proteins

The de novo design of catalytic proteins provides a stringent test of our understanding of enzyme function, while simultaneously laying the groundwork for the design of novel catalysts. Here we describe the design of an O-2-dependent phenol oxidase whose structure, sequence, and activity are designed from first principles. The protein catalyzes the two-electron oxidation of 4-aminophenol (k(cat)/K-m = 1,500 M(-1.)min(-1)) to the corresponding quinone monoimine by using a diiron cofactor. The catalytic efficiency is sensitive to changes of the size of a methyl group in the protein, illustrating the specificity of the design.