Nobel prize 2018: New review on Directed Evolution
Today, the Nobel Prizes are awarded in Stockholm. The 2018 Nobel Prize in Chemistry was devided: One half will be awarded to Frances H. Arnold for the development of the directed evolution of enzymes and the other half will be awarded jointly to George P. Smith and Sir Gregory P. Winter for the phage display of peptides and antibodies.
Directed evolution affects our everyday life enormously. Only through directed evolution proteins can be tailored for the chemical, pharmaceutical, as well as for the food, animal feed and detergent industry.
In honor of this year's Nobel Prize laureates, Prof. Bornscheuer, Prof. Hauer, Prof. Jaeger and Prof. Schwaneberg describe and discuss the significance of directed evolution for the scientific community and its social benefits in an article published in Angewandte Chemie International Edition .
Link to the review: https://onlinelibrary.wiley.com/doi/10.1002/anie.201812717
Principles of directed enzyme evolution and phage display of peptides and antibodies.
A) Directed evolution to improve the properties of an enzyme by iterative cycles of mutagenesis, high-throughput screening, or selection, and subsequent identification of improved variants. (1.) Random mutations are introduced into a target gene, (2.) for example, by error-prone PCR (epPCR). The mutated genes are transferred into a suitable host organism and expressed. (3) , thereby resulting in a large library of protein or enzyme variants. Improved variants are then identified (4) either by high-throughput screening or by selection for a desired property. The gene(s) encoding such improved variant(s) are isolated and used for another cycle of directed evolution
B) Phage display to present heterologous peptides on the surface of a phage (upper panel) andits use for the production of antibodies (lower panel). Heterologous peptides can be displayed on the surface of a phage by cloning a respective (5) gene into the phage DNA as a genetic fusion with a phage capsule protein (6). After expression of the phage DNA (7) the target peptide isdisplayed as a fusion with the host capsule protein. By using antibodies against the displayed peptide, the displaying phages can be “fished” (8) and propagated, thus allowing the subsequent retrieval of the gene encoding the displayed peptide. As an extension of this technique, antibody fragments can also be displayed directly. A phage library carrying a large number of genetic fusions of a gene coding for a phage capsule proteinand genetic variations of a desired antibody binding site can be created. (9) An affinity selection approach (termed “panning”) can then be used to identify high-affinity antibody fragments binding to a target antigen which is exposed and immobilized on a surface. (10) Phages binding withhigh affinity can be “fished” and isolated prior to a next cycle of panning. (11) This technique allows the identification of extremely high-affinity antibody fragments, thus circumventing laborious hybridoma technologies or conventional immunization.