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Publication Abstract from PubMed

FeFe]-hydrogenases efficiently catalyze the reversible oxidation of molecular hydrogen. Their prowess stems from the intricate H-cluster, combining a [Fe4S4] center with a binuclear iron center ([2Fe]H). In the latter, each iron atom is coordinated by a CO and CN ligand, connected by a CO and an azadithiolate ligand. The synthesis of this active site involves a unique multiprotein assembly, featuring radical SAM proteins HydG and HydE. HydG initiates the transformation of L-tyrosine into cyanide and carbon monoxide to generate complex-B, which is subsequently transferred to HydE to continue the biosynthesis of the [2Fe]H-subcluster. Due to its instability, complex-B isolation for structural or spectroscopic characterization has been elusive this far. Nevertheless, the use of a biomimetic compound of complex-B allowed circumventing the need for the HydG protein during in vitro functional investigations, implying a similar structure for complex-B. Here, we used the HydE protein as a nanocage to encapsulate and stabilize the complex-B product generated by HydG. Using X-ray crystallography, we successfully determined its structure at 1.3 A resolution. Furthermore, we demonstrated that complex-B is directly transferred from HydG to HydE, thus not being released into the solution post-synthesis, highlighting a transient interaction between the two proteins.

Maturation of the [FeFe]-Hydrogenase: Direct Transfer of the (kappa3-cysteinate)FeII(CN)(CO)2 Complex-B from HydG to HydE.,Omeiri J, Martin L, Usclat A, Cherrier MV, Nicolet Y Angew Chem Int Ed Engl. 2023 Nov 14:e202314819. doi: 10.1002/anie.202314819. PMID:37962296^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.