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

Catalytic Hydrogenation of meso-Octamethylporphyrinogen (Calix[4]pyrrole)

Journot, Guillaume ; Letondor, Christophe ; Neier, Reinhard ; Stoeckli-Evans, Helen ; Savoia, Diego ; Gualandi, Andrea

In: Chemistry - A European Journal, 2010, vol. 16, no. 4, p. 4224-4230

Hydrogenation of meso-octamethylporphyrinogen (calix[4]pyrrole) with a number of heterogeneous catalysts under different experimental conditions has been investigated. GC-MS analyses of the reaction mixtures showed the formation of one to four products in low to moderate yields: three of them were diastereoisomers of the product derived from half-hydrogenation of the substrate, and displayed...

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

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...