Enzyme Design

The replacement of amino acids in a protein may generate a new biological function (plasticity). Simultaneous incorporation and adjustment of functional elements by insertion, deletion, mutation, and substitution of several active sites into an existing protein scaffold causes new catalytic activity. The introduction of β-lactamase activity into a metallohydrolase scaffold of glyoxalase II resulted in the creation of a new metallolactamase that lost its original activity but catalyzed the hydrolysis of cefotaxime and increased the resistance of E. coli to this antibiotic by ∼100 fold. (Park H-S et al 2006 Science 311:535). Genuinely new enzymatic activities can be created de novo, without the need for prior mechanistic information, by selection from a naive protein library (>10¹²) of very high diversity, with product formation as the sole selection criterion. Ligases have been selected this way with rate enhancements of more than two-million-fold (Seelig B, Szostak JW 2007 Nature...