5 publications

5 publications

A Structural View of Synthetic Cofactor Integration into [FeFe]-Hydrogenases

Apfel, U.-P.; Happe, T.; Kurisu, G.

Chem. Sci. 2016, 7, 959-968, 10.1039/C5SC03397G

Crystal structures of semisynthetic [FeFe]-hydrogenases with variations in the [2Fe] cluster show little structural differences despite strong effects on activity.


Metal: Fe
Ligand type: CN; CO; Dithiolate
Anchoring strategy: Dative
Optimization: Chemical
Reaction: H2 evolution
Max TON: ---
ee: ---
PDB: 4XDC
Notes: H2 evolution activity of the ArM: 2874 (mmol H2)*min-1*(mg protein)-1.

Chalcogenide Substitution in the [2Fe] Cluster of [FeFe]-Hydrogenases Conserves High Enzymatic Activity

Apfel, U.-P.; Happe, T.

Dalton Trans. 2017, 46, 16947-16958, 10.1039/C7DT03785F

Combination of biological and chemical methods allow for creation of [FeFe]-hydrogenases with an artificial synthetic cofactor.


Metal: Fe
Ligand type: CN; CO; Diselenolate
Anchoring strategy: Dative
Optimization: Chemical
Reaction: H2 evolution
Max TON: ---
ee: ---
PDB: 5OEF
Notes: ---

Generation of a Functional, Semisynthetic [FeFe]-Hydrogenase in a Photosynthetic Microorganism

Berggren, G.; Lindblad, P.

Energy Environ. Sci. 2018, 11, 3163-3167, 10.1039/C8EE01975D

[FeFe]-Hydrogenases are hydrogen producing metalloenzymes with excellent catalytic capacities, highly relevant in the context of a future hydrogen economy. Here we demonstrate the synthetic activation of a heterologously expressed [FeFe]-hydrogenase in living cells of Synechocystis PCC 6803, a photoautotrophic microbial chassis with high potential for biotechnological energy applications. H2-Evolution assays clearly show that the non-native, semi-synthetic enzyme links to the native metabolism in living cells.


Metal: Fe
Ligand type: CN; CO
Anchoring strategy: Reconstitution
Optimization: Chemical & genetic
Reaction: H2 evolution
Max TON: ---
ee: ---
PDB: ---
Notes: ---

Hybrid [FeFe]-Hydrogenases with Modified Active Sites Show Remarkable Residual Enzymatic Activity

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.


Metal: Fe
Ligand type: CN; CO; Dithiolate
Anchoring strategy: Dative
Optimization: Chemical
Max TON: ---
ee: ---
PDB: ---
Notes: H2 evolution: TOF = 450 s-1. H2 oxidation: TOF = 150 s-1.

Spontaneous Activation of [FeFe]-Hydrogenases by an Inorganic [2Fe] Active Site Mimic

Happe, T.

Nat. Chem. Biol. 2013, 9, 607-609, 10.1038/Nchembio.1311

Hydrogenases catalyze the formation of hydrogen. The cofactor ('H-cluster') of [FeFe]-hydrogenases consists of a [4Fe-4S] cluster bridged to a unique [2Fe] subcluster whose biosynthesis in vivo requires hydrogenase-specific maturases. Here we show that a chemical mimic of the [2Fe] subcluster can reconstitute apo-hydrogenase to full activity, independent of helper proteins. The assembled H-cluster is virtually indistinguishable from the native cofactor. This procedure will be a powerful tool for developing new artificial H2-producing catalysts.


Metal: Fe
Ligand type: CN; CO; Dithiolate
Anchoring strategy: Dative
Optimization: Chemical
Reaction: H2 evolution
Max TON: ---
ee: ---
PDB: ---
Notes: ---