4XDC

Active semisynthetic [FeFe]-hydrogenase CpI with aza-dithiolato-bridged [2Fe] cofactor

Summary for 4XDC

• Entry DOI: 10.2210/pdb4xdc/pdb
• Related: 4XDC
• Descriptor: Iron hydrogenase 1, dicarbonyl[bis(cyanide-kappaC)]-mu-(iminodimethanethiolatato-1kappaS:2kappaS)-mu-(oxomethylidene)diiron(2+), IRON/SULFUR CLUSTER, ... (6 entities in total)
• Functional Keywords: hydrogenase, h-cluster, oxidoreductase
• Biological source: Clostridium pasteurianum; More
• Total number of polymer chains: 2
• Total formula weight: 134219.01

Authors

Esselborn, J.,Hofmann, E.,Kurisu, G.,Happe, T. (deposition date: 2014-12-19, release date: 2015-11-11, Last modification date: 2024-01-10)

Primary citation

Esselborn, J.,Muraki, N.,Klein, K.,Engelbrecht, V.,Metzler-Nolte, N.,Apfel, U.P.,Hofmann, E.,Kurisu, G.,Happe, T.
A structural view of synthetic cofactor integration into [FeFe]-hydrogenases.
Chem Sci, 7:959-968, 2016

PubMed Abstract: [FeFe]-hydrogenases are nature's fastest catalysts for the evolution or oxidation of hydrogen. Numerous synthetic model complexes for the [2Fe] subcluster (2Fe) of their active site are known, but so far none of these could compete with the enzymes. The complex Fe[μ-(SCH)X](CN)(CO) with X = NH was shown to integrate into the apo-form of [FeFe]-hydrogenases to yield a fully active enzyme. Here we report the first crystal structures of the apo-form of the bacterial [FeFe]-hydrogenase CpI from at 1.60 Å and the active semisynthetic enzyme, CpI, at 1.63 Å. The structures illustrate the significant changes in ligand coordination upon integration and activation of the [2Fe] complex. These changes are induced by a rigid 2Fe cavity as revealed by the structure of apoCpI, which is remarkably similar to CpI. Additionally we present the high resolution crystal structures of the semisynthetic bacterial [FeFe]-hydrogenases CpI (X = CH), CpI (X = O) and CpI (X = S) with changes in the headgroup of the dithiolate bridge in the 2Fe cofactor. The structures of these inactive enzymes demonstrate that the 2Fe-subcluster and its protein environment remain largely unchanged when compared to the active enzyme CpI. As the active site shows an open coordination site in all structures, the absence of catalytic activity is probably not caused by steric obstruction. This demonstrates that the chemical properties of the dithiolate bridge are essential for enzyme activity.

PubMed: 29896366
DOI: 10.1039/c5sc03397g

Experimental method

X-RAY DIFFRACTION (1.63 Å)