Artero, V.

ChemPlusChem 2016, 81, 1083-1089, 10.1002/cplu.201600218

The insertion of cobaloxime catalysts in the heme‐binding pocket of heme oxygenase (HO) yields artificial hydrogenases active for H2 evolution in neutral aqueous solutions. These novel biohybrids have been purified and characterized by using UV/visible and EPR spectroscopy. These analyses revealed the presence of two distinct binding conformations, thereby providing the cobaloxime with hydrophobic and hydrophilic environments, respectively. Quantum chemical/molecular mechanical docking calculations found open and closed conformations of the binding pocket owing to mobile amino acid residues. HO‐based biohybrids incorporating a {Co(dmgH)2} (dmgH2=dimethylglyoxime) catalytic center displayed up to threefold increased turnover numbers with respect to the cobaloxime alone or to analogous sperm whale myoglobin adducts. This study thus provides a strong basis for further improvement of such biohybrids, using well‐designed modifications of the second and outer coordination spheres, through site‐directed mutagenesis of the host protein.

Okamoto, Y.; Ward, T.R.

Comprehensive Supramolecular Chemistry II 2017, 459-510, 10.1016/B978-0-12-409547-2.12551-X

Artificial metalloenzymes result from the incorporation of an organometallic moiety within a macromolecule. In this article, we review the field of artificial metalloenzymes. These are classified according to the host that accommodates the organometallic cofactor: cyclodextrins (“Cyclodextrin-Based Artificial Enzymes” section), ligands bearing a substrate recognition motif (“Artificial Enzymes With Ligands Bearing Substrate Recognition Motifs” section), supramolecular cages (“Cage Molecules as Artificial Enzymes” section), nucleic acids (“DNA-Based Artificial Metalloenzymes” section), and proteins (“Protein-Based Artificial Enzymes” section). Both dative and supramolecular anchoring strategies are reviewed.