Artificial Hydrogenases Based on Cobaloximes and Heme Oxygenase
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- 作者：Dr. Marine Bacchi ; Elias Veinberg ; Dr. Martin J. Field ; Dr. Jens Niklas ; Dr. Toshitaka Matsui ; Dr. D. M. Tiede ; Dr. Oleg G. Poluektov ; Prof. Masao Ikeda-Saito ; Prof. Marc Fontecave and Dr. Vincent Artero
- 刊名：ChemPlusChem
- 出版年：2016
- 出版时间：October 2016
- 年：2016
- 卷：81
- 期：10
- 页码：1083-1089
- 全文大小：1239K
- ISSN：2192-6506
文摘
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.