Directed Evolution: Novel and Improved Enzymes

Abstract By mimicking Darwinian evolution in the test tube, directed evolution has become a powerful tool for engineering novel enzymes for basic and applied biology research and medicine. Unlike structure‐based rational design, directed evolution is capable of altering single or multiple functional properties such as activity, specificity, selectivity, stability, and solubility of naturally occurring enzymes in the absence of detailed knowledge of enzyme structure, function, or mechanism. More recently, directed evolution has also been used to engineer metabolic pathways, viruses, and whole microorganisms, and to address fundamental problems in biology. The success of directed evolution has been largely fueled by the development of numerous molecular biology techniques that enable the creation of genetic diversity through random mutagenesis or homologous or nonhomologous recombination in the target genes and the development of powerful high throughput screening or selection methods as well as by novel applications. This review will highlight the key developments in directed evolution and focus on the design and engineering of novel enzymes through directed evolution and their implications in chemical biology.