Cavazza, C.; Ménage, S.

Angew. Chem. Int. Ed. 2013, 52, 3922-3925, 10.1002/anie.201209021

The substrate for an artificial iron monooxygenase was selected by using docking calculations. The high catalytic efficiency of the reported enzyme for sulfide oxidation was directly correlated to the predicted substrate binding mode in the protein cavity, thus illustrating the synergetic effect of the substrate binding site, protein scaffold, and catalytic site.

Cavazza, C.; Ménage, S.

J. Am. Chem. Soc. 2017, 139, 17994-18002, 10.1021/jacs.7b09343

Designing systems that merge the advantages of heterogeneous catalysis, enzymology, and molecular catalysis represents the next major goal for sustainable chemistry. Cross-linked enzyme crystals display most of these essential assets (well-designed mesoporous support, protein selectivity, and molecular recognition of substrates). Nevertheless, a lack of reaction diversity, particularly in the field of oxidation, remains a constraint for their increased use in the field. Here, thanks to the design of cross-linked artificial nonheme iron oxygenase crystals, we filled this gap by developing biobased heterogeneous catalysts capable of oxidizing carbon–carbon double bonds. First, reductive O2 activation induces selective oxidative cleavage, revealing the indestructible character of the solid catalyst (at least 30 000 turnover numbers without any loss of activity). Second, the use of 2-electron oxidants allows selective and high-efficiency hydroxychlorination with thousands of turnover numbers. This new technology by far outperforms catalysis using the inorganic complexes alone, or even the artificial enzymes in solution. The combination of easy catalyst synthesis, the improvement of “omic” technologies, and automation of protein crystallization makes this strategy a real opportunity for the future of (bio)catalysis.

Lubitz, W.; Reijerse, E.

Biochemistry 2015, 54, 1474-1483, 10.1021/bi501391d

[FeFe]-hydrogenases are to date the only enzymes for which it has been demonstrated that the native inorganic binuclear cofactor of the active site Fe2(adt)(CO)3(CN)2 (adt = azadithiolate = [S-CH2-NH-CH2-S]2–) can be synthesized on the laboratory bench and subsequently inserted into the unmaturated enzyme to yield fully functional holo-enzyme (Berggren, G. et al. (2013) Nature 499, 66–70; Esselborn, J. et al. (2013) Nat. Chem. Biol. 9, 607–610). In the current study, we exploit this procedure to introduce non-native cofactors into the enzyme. Mimics of the binuclear subcluster with a modified bridging dithiolate ligand (thiodithiolate, N-methylazadithiolate, dimethyl-azadithiolate) and three variants containing only one CN– ligand were inserted into the active site of the enzyme. We investigated the activity of these variants for hydrogen oxidation as well as proton reduction and their structural accommodation within the active site was analyzed using Fourier transform infrared spectroscopy. Interestingly, the monocyanide variant with the azadithiolate bridge showed ∼50% of the native enzyme activity. This would suggest that the CN– ligands are not essential for catalytic activity, but rather serve to anchor the binuclear subsite inside the protein pocket through hydrogen bonding. The inserted artificial cofactors with a propanedithiolate and an N-methylazadithiolate bridge as well as their monocyanide variants also showed residual activity. However, these activities were less than 1% of the native enzyme. Our findings indicate that even small changes in the dithiolate bridge of the binuclear subsite lead to a rather strong decrease of the catalytic activity. We conclude that both the Brønsted base function and the conformational flexibility of the native azadithiolate amine moiety are essential for the high catalytic activity of the native enzyme.

Cavazza, C.; Ménage, S.

ChemBioChem 2009, 10, 545-552, 10.1002/cbic.200800595

Magic Mn–salen metallozyme: The design of an original, artificial, inorganic, complex‐protein adduct, has led to a better understanding of the synergistic effects of both partners. The exclusive formation of sulfoxides by the hybrid biocatalyst, as opposed to sulfone in the case of the free inorganic complex, highlights the modulating role of the inorganic‐complex‐binding site in the protein.