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Université de Neuchâtel

Artificial Metalloenzymes: (Strept)avidin as Host for Enantioselective Hydrogenation by Achiral Biotinylated Rhodium−Diphosphine Complexes

Skander, Myriem ; Humbert, Nicolas ; Collot, Jérôme ; Gradinaru, Julieta ; Klein, Gérard ; Loosli, Andreas ; Sauser, Jérôme ; Zocchi, Andrea ; Gilardoni, François ; Ward, Thomas R.

In: Journal of the American Chemical Society (JACS), 2004, vol. 126, no. 44, p. 14411–14418

We report on the generation of artificial metalloenzymes based on the noncovalent incorporation of biotinylated rhodium−diphosphine complexes in (strept)avidin as host proteins. A chemogenetic optimization procedure allows one to optimize the enantioselectivity for the reduction of acetamidoacrylic acid (up to 96% ee (R) in streptavidin S112G and up to 80% ee (S) in WT avidin)....

Université de Neuchâtel

Artificial Metalloenzymes for Enantioselective Catalysis Based on Biotin−Avidin

Collot, Jérôme ; Gradinaru, Julieta ; Humbert, Nicolas ; Skander, Myriem ; Zocchi, Andrea ; Ward, Thomas R.

In: Journal of the American Chemical Society (JACS), 2003, vol. 125, no. 30, p. 9030-9031

Incorporation of biotinylated racemic three-legged d6-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...

Université de Neuchâtel

Artificial Transfer Hydrogenases Based on the Biotin−(Strept)avidin Technology: Fine Tuning the Selectivity by Saturation Mutagenesis of the Host Protein

Letondor, Christophe ; Pordea, Anca ; Humbert, Nicolas ; Ivanova, Anita ; Mazurek, Sylwester ; Novic, Marjana ; Ward, Thomas R.

In: Journal of the American Chemical Society (JACS), 2006, vol. 128, no. 25, p. 8320-8328

Incorporation of biotinylated racemic three-legged d6-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...

Université de Neuchâtel

Second Generation Artificial Hydrogenases Based on the Biotin-Avidin Technology: Improving Activity, Stability and Selectivity by Introduction of Enantiopure Amino Acid Spacers

Rusbandi, Untung E. ; Lo, Cheikh ; Skander, Myriem ; Ivanova, Anita ; Creus, Marc ; Humbert, Nicolas ; Ward, Thomas R.

In: Advanced Synthesis & Catalysis, 2007, vol. 349, no. 11-12, p. 1923-1930

We report on our efforts to create efficient artificial metalloenzymes for the enantioselective hydrogenation of N-protected dehydroamino acids using either avidin or streptavidin as host proteins. Introduction of chiral amino acid spacers - phenylalanine or proline - between the biotin anchor and the flexible aminodiphosphine moiety 1, combined with saturation mutagenesis at...

Université de Neuchâtel

Electrophoretic behavior of streptavidin complexed to a biotinylated probe : A functional screening assay for biotin-binding proteins

Humbert, Nicolas ; Zocchi, Andrea ; Ward, Thomas R.

In: Electrophoresis, 2004, vol. 26, p. 47-52

The biotin-binding protein streptavidin exhibits a high stability against thermal denaturation, especially when complexed to biotin. Herein we show that, in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), streptavidin is stabilized at high temperature in the presence of biotinylated fluorescent probes, such as biotin-4-fluorescein, which is incorporated within the binding...

Université de Neuchâtel

Aqueous oxidation of alcohols catalyzed by artificial metalloenzymes based on the biotin–avidin technology

Thomas, Christophe M. ; Letondor, Christophe ; Humbert, Nicolas ; Ward, Thomas R.

In: Journal of Organometallic Chemistry, 2005, vol. 690, p. 4488-4491

Based on the incorporation of biotinylated organometallic catalyst precursors within (strept)avidin, we have developed artificial metalloenzymes for the oxidation of secondary alcohols using tert-butylhydroperoxide as oxidizing agent. In the presence of avidin as host protein, the biotinylated aminosulfonamide ruthenium piano stool complex 1 (0.4 mol%) catalyzes the oxidation of...

Université de Neuchâtel

Crystallographic Analysis of a Full-length Streptavidin with Its C-terminal Polypeptide Bound in the Biotin Binding Site

Le Trong, Isolde ; Humbert, Nicolas ; Ward, Thomas R. ; Stenkamp, Ronald E.

In: Journal of Molecular Biology, 2006, vol. 356, p. 738-745

The structure of a full-length streptavidin has been determined at 1.7 Å resolution and shows that the 20 residue extension at the C terminus forms a well-ordered polypeptide loop on the surface of the tetramer. Residues 150–153 of the extension are bound to the ligand-binding site, possibly competing with exogenous ligands. The binding mode of these residues is compared with that of biotin...

Université de Neuchâtel

Artificial metalloenzymes for enantioselective catalysis : the phenomenon of protein accelerated catalysis

Collot, Jérôme ; Humbert, Nicolas ; Skander, Myriem ; Klein, Gérard ; Ward, Thomas R.

In: Journal of Organometallic Chemistry, 2005, vol. 689, p. 4868-4871

We report on the phenomenon of protein-accelerated catalysis in the field of artificial metalloenzymes based on the non-covalent incorporation of biotinylated rhodium–diphosphine complexes in (strept)avidin as host proteins. By incrementally varying the [Rh(COD)(Biot-1)]+ vs. (strept)avidin ratio, we show that the enantiomeric excess of the produced acetamidoalanine decreases slowly....

Université de Neuchâtel

Artificial metalloenzymes based on biotin-avidin technology for the enantioselective reduction of ketones by transfer hydrogenation

Letondor, Christophe ; Humbert, Nicolas ; Ward, Thomas R.

In: Proceedings of the National Academy of Sciences of the USA (PNAS), 2005, vol. 102, p. 4683-4687

Most physiological and biotechnological processes rely on molecular recognition between chiral (handed) molecules. Manmade homogeneous catalysts and enzymes offer complementary means for producing enantiopure (single-handed) compounds. As the subtle details that govern chiral discrimination are difficult to predict, improving the performance of such catalysts often relies on trial-and-error...