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Artificial Hydrogenases Based on Cobaloximes and Heme Oxygenase
Author(s) -
Bacchi Marine,
Veinberg Elias,
Field Martin J.,
Niklas Jens,
Matsui Toshitaka,
Tiede D. M.,
Poluektov Oleg G.,
IkedaSaito Masao,
Fontecave Marc,
Artero Vincent
Publication year - 2016
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201600218
Subject(s) - chemistry , hydrogenase , myoglobin , heme , active site , catalysis , aqueous solution , hemeprotein , docking (animal) , stereochemistry , combinatorial chemistry , enzyme , organic chemistry , medicine , nursing
The insertion of cobaloxime catalysts in the heme‐binding pocket of heme oxygenase (HO) yields artificial hydrogenases active for H 2 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 } (dmgH 2 =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.