An Artificial Enzyme Made by Covalent Grafting of an Fe-II Complex into beta-Lactoglobulin: Molecular Chemistry, Oxidation Catalysis, and Reaction-Intermediate Monitoring in a Protein

作者：Buron Charlotte; Senechal David Katell; Ricoux Remy; Le Caer Jean Pierre; Guerineau Vincent; Mejanelle Philippe; Guillot Regis; Herrero Christian; Mahy Jean Pierre^*; Banse Frederic

来源：Chemistry - A European Journal, 2015, 21(34): 12188-12193.

DOI：10.1002/chem.201501755

• bioinorganic chemistry
• coordination compounds
• enzyme catalysis
• enzyme models
• iron

An artificial metalloenzyme based on the covalent grafting of a nonheme Fe-II polyazadentate complex into bovine -lactoglobulin has been prepared and characterized by using various spectroscopic techniques. Attachment of the Fe-II catalyst to the protein scaffold is shown to occur specifically at Cys121. In addition, spectrophotometric titration with cyanide ions based on the spin-state conversion of the initial high spin (S=2) Fe-II complex into a low spin (S=0) one allows qualitative and quantitative characterization of the metal center's first coordination sphere. This biohybrid catalyst activates hydrogen peroxide to oxidize thioanisole into phenylmethylsulfoxide as the sole product with an enantiomeric excess of up to 20%. Investigation of the reaction between the biohybrid system and H2O2 reveals the generation of a high spin (S=5/2) Fe-III((2)-O-2) intermediate, which is proposed to be responsible for the catalytic sulfoxidation of the substrate.

• 出版日期2015-8-17