Directed Evolution for the Discovery of Engineered Proteins and Small Peptides Using Molecular Mutagenesis

Random mutagenesis is an essential technique in the directed evolution of proteins and peptides, driving advancements in protein engineering and biotechnology. This review provides a critical analysis of various error-prone polymerase chain reaction (epPCR) techniques employed for random mutagenesis, highlighting their mechanisms, advantages, and limitations. We compare conventional methods with emerging approaches, including combinative techniques and specialized protocols for small amplicons. We also discuss a few alternative approaches for cloning a mutant gene library, which could be simpler and more efficient than the traditional restriction digestion-ligation method, significantly improving the directed evolution workflows. Ultimately, the selection of a suitable method should align with the specific goals of the research, accepting inherent trade-offs. By combining different mutagenesis techniques with complementary mutational spectra, researchers can optimize their strategies for the discovery of novel proteins and peptides with specific biological activities and physicochemical properties of interest.