Progress in strategies for sequence diversity library creation for directed evolution

Protein engineering has been the most attractive strategy for biologists to redesign enzymes. As the simplest technique of protein engineering, directed evolution has been applied to many fields, such as industry, agriculture and medicine. An experiment of directed evolution comprises mutant libraries creation and screening or selection for enzyme variants with desired properties. Therefore, a successful application of directed evolution depends on whether or not one can generate a quality library and perform effective screening to find the desired properties. Directed evolution is already increasingly used in many laboratories to improve protein stability and activity, alter enzyme substrate specificity, or design new activities. Meanwhile, many more effective novel strategies of mutant library generation and screening or selection have emerged in recent years, and will continue to be developed. Combining computational/rational design with directed evolution has been developed as more available means to redesign enzymes. Keywords: Protein engineering, directed evolution, sequence diversity creation, novel strategy, computational design, rational design