Designing Chimera Baeyer-Villiger Biooxidation Catalysts

15.08.2006 - 15.08.2009
Research funding project
Oxygenases carry out the chemo-, regio-, and stereoselective introduction of molecular oxygen into organic molecules. Based on the nature of the oxidant (O2) and the degradability of enzymatic catalysts, this approach represents a green and highly sustainable methodology for environmentally benign oxidation reactions. The stereoselective Baeyer-Villiger oxidation of ketones to the corresponding chiral lactones is one of the prominent domains for biocatalysis, as enzymes are by far superior catalytic entities compared to de-novo designed organometal catalysts with respect to selectivity. However, the necessity to provide and recycle required cofactors and the limited stability of Baeyer-Villiger monooxygenases (BVMOs) has prevented wide-spread application among the community of synthetic chemists, so far. Recently, we could demonstrate the feasibility of whole-cell mediated Baeyer-Villiger biooxidations utilizing recombinant organisms designed to overexpress the required biocatalyst. Such microbial strains are easy-to-use catalytic systems and allow the gram scale synthesis of chiral lactones as key precursors for natural products and bioactive compounds on laboratory scale. This project aims at overcoming the last major obstacle en route to readily applicable BVMOs in every day synthetic applications by designing novel thermostable chimera enzymes. Such -BVMOs will be designed by gene shuffling of a thermostable enzyme from a moderately thermophilic organism (PAMO) with BVMOs of bacterial origin. While PAMO displays a very limited substrate profile ¿ hence, making it an unlikely candidate for general applications in catalysis ¿ there is a considerable number of other BVMOs with well described and broad ketone tolerance allowing in addition the preparation of enantiocomplementary lactone products. By combining PAMO and bacterial BVMOs as parent enzymes into new -BVMOs, high-throughput screening techniques with fluorescence assays are expected to provide candidates with a recombination of beneficial properties. In a second stage, such novel biocatalysts will be optimized using random and knowledge-based approaches in molecular biology in an iterative process. At the end of these efforts, a set of -BVMOs will become available, which displays broad substrate specificities and high stereoselectivites combined with an improved thermal stability. This will facilitate the chiral Baeyer-Villiger biooxidation to become an easily applicable tool in stereoselective synthesis. In addition, novel indications on the key structural areas of high impact for biocatalyst efficiency are expected for BVMOs, in general, providing a better understanding of this fascinating enzyme family.

People

Project leader

Project personnel

Institute

Grant funds

  • FWF - Österr. Wissenschaftsfonds (National) Austrian Science Fund (FWF)

Research focus

  • Biological and Bioactive Materials: 50%
  • Sustainable Production and Technologies: 30%
  • Materials Characterization: 20%

Keywords

GermanEnglish
gene shufflinggene shuffling
Biokatalysebiocatalysis
Thermostabilitätthermostability
Enzymmodifikationenzyme modification
Asymetrische Syntheseasymmetric synthesis

Publications