Directed Evolution of Stereoselective Enzymes: A Prolific Source of Catalysts for Asymmetric Reactions
Event details
| Date | 13.11.2013 |
| Hour | 17:15 › 18:30 |
| Speaker |
Prof. Dr. Dr. h.c. Manfred T. Reetz (Emeritus), Chemistry Department, Philipps-Universität, 35032 Marburg/Germany and Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Germany |
| Location | |
| Category | Conferences - Seminars |
Enzymes have been used as catalysts in synthetic organic chemistry and in biotechnology for a long time, but they have traditionally suffered from the following often observed limitations: 1) Narrow substrate scope; 2) Insufficient stereo- or regioselectivity. During the last 15 years the methods of directed evolution have eliminated these restrictions, thereby providing a prolific and inexhaustible source of catalysts for a variety of applications. It involves repeated cycles of gene mutagenesis, expression and screening (or selection). When we started our research in this area in the mid-1990s, several gene mutagenesis methods had already been developed by molecular biologists, including error-prone polymerase chain reaction (epPCR), saturation mutagenesis and DNA shuffling, and a few reports regarding the enhancement of enzyme stability had appeared. In contrast, we were interested in a very different catalytic parameter, namely stereoselectivity. Early proof-of-principle was delivered in 1997 using a lipase in the hydrolytic kinetic resolution of racemic ester, four rounds of epPCR being employed as the mutagenesis method. However, epPCR proved not to be the optimal strategy, and therefore the combination of epPCR, DNA shuffling and saturation mutagenesis was tested. By 2005 many academic and industrial groups had joined efforts in this new research area using these methods, although the question of efficiency was not addressed. Screening is the bottleneck of directed evolution, which means that if truly practical strategies for probing protein sequence space can be put into practice with generation of highest-quality mutant libraries, then the whole evolutionary process will be fast, efficient and reliable. Our contribution in this endeavor is iterative saturation mutagenesis (ISM), which fulfills all requirements for advanced directed evolution. Stereo- and regioselectivity as well as the extension of substrate scope (rate) can now be achieved while minimizing laboratory work. Examples pertain to the evolution of stereo- and regioselective enzymes such as hydrolases, Baeyer-Villiger monooxygenases (C-C activation) and P450 monooxgenases (C-H activation). Review of directed evolution: Angew. Chem. Int. Ed. 2011, 50, 138-174; Perspective on biocatalysis in organic chemistry: J. Am. Chem. Soc. 2013; DOI: 10.1021/ja405051f.
Practical information
- General public
- Free
Organizer
- Prof. Kai Johnsson
[email protected]
Contact
- Prof. Kai Johnsson
[email protected]