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Artificial Metalloenzymes for Enantioselective Catalysis Based on Biotin−Avidin
Auteur(s)
Collot, Jérôme
Gradinaru, Julieta
Humbert, Nicolas
Skander, Myriem
Zocchi, Andrea
Ward, Thomas R.
Date de parution
2003
In
Journal of the American Chemical Society (JACS), American Chemical Society (ACS), 2003/125/30/9030-9031
Résumé
Incorporation of biotinylated racemic three-legged d<sup>6</sup>-piano stool complexes in streptavidin yields enantioselective transfer hydrogenation artificial metalloenzymes for the reduction of ketones. Having identified the most promising organometallic catalyst precursors in the presence of wild-type streptavidin, fine-tuning of the selectivity is achieved by saturation mutagenesis at position S112. This choice for the genetic optimization site is suggested by docking studies which reveal that this position lies closest to the biotinylated metal upon incorporation into streptavidin. For aromatic ketones, the reaction proceeds smoothly to afford the corresponding enantioenriched alcohols in up to 97% ee (<i>R</i>) or 70% (<i>S</i>). On the basis of these results, we suggest that the enantioselection is mostly dictated by CH/π interactions between the substrate and the η<sup>6</sup>-bound arene. However, these enantiodiscriminating interactions can be outweighed in the presence of cationic residues at position S112 to afford the opposite enantiomers of the product.
Identifiants
Type de publication
journal article
