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

Création de métalloenzymes artificielles basées sur la technologie biotine-avidine pour la réduction asymétrique de dérivés carbonylés par transfert hydrogénant

Letondor, Christophe ; Ward, Thomas R. (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2006 ; 1866.

Homogenous- and enzymatic catalysis are in many respects complementary for the synthesis of enantiopure 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 procedures. Homogenous catalysts are optimized by chemical modification of the first coordination sphere and enzymes can be...

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...