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Prof. Thomas R. Ward (University of Neuchâtel, Švýcarsko)
Artificial Metalloenzymes for Enantioselective Catalysis Based on the Biotin-Avidin Technology
Abstrakt
Homogeneous- and enzymatic catalysis offer complementary means to generate enantiomerically pure compounds. Incorporation of achiral biotinylated rhodiumdiphosphine complexes into (strep)avidin yields artificial metalloenzymes for the hydrogenation of N-protected dehydroaminoacids (Scheme). A chemogenetic optimization procedure allows to produce both enantiomers of acetamidoalanine in good enantioselectivity (up to 96% ee). Analysis of the performance of these hybrid catalysts reveal features reminsiscent both of enzymatic and of homogeneous systems.
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Scheme. Artificial metalloenzymes for enantioselective hydrogenation reactions. The host protein (either avidin or streptavidin) displays a high affinity for the biotin anchor. Introduction of a spacer and variation of the ligand scaffold allows to chemically optimize the enantioselectivity. Fine tuning of the selectivity can be achieved via site-directed mutagenesis of the (strept)avidin.
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