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Structure-function relationships in [FeFe]-hydrogenase active site maturation.

ABSTRACT: Since the discovery that, despite the active site complexity, only three gene products suffice to obtain active recombinant [FeFe]-hydrogenase, significant light has been shed on this process. Both the source of the CO and CN(-) ligands to iron and the assembly site of the catalytic subcluster are known, and an apo structure of HydF has been published recently. However, the nature of the substrate(s) for the synthesis of the bridging dithiolate ligand to the subcluster remains to be established. From both spectroscopy and model chemistry, it is predicted that an amine function in this ligand plays a central role in catalysis, acting as a base in the heterolytic cleavage of hydrogen.

SUBMITTER: Nicolet Y

PROVIDER: S-EPMC3340144 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature

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Structure-function relationships in [FeFe]-hydrogenase active site maturation.

Nicolet Yvain Y Fontecilla-Camps Juan C JC

The Journal of biological chemistry 20120302 17

Since the discovery that, despite the active site complexity, only three gene products suffice to obtain active recombinant [FeFe]-hydrogenase, significant light has been shed on this process. Both the source of the CO and CN(-) ligands to iron and the assembly site of the catalytic subcluster are known, and an apo structure of HydF has been published recently. However, the nature of the substrate(s) for the synthesis of the bridging dithiolate ligand to the subcluster remains to be established. ...[more]

PMID: 22389497

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| S-EPMC4210170 | biostudies-literature

Borane-protected cyanides as surrogates of H-bonded cyanides in [FeFe]-hydrogenase active site models.

Project description:Triarylborane Lewis acids bind [Fe2(pdt)(CO)4(CN)2](2-) [1](2-) (pdt(2-) = 1,3-propanedithiolate) and [Fe2(adt)(CO)4(CN)2](2-) [3](2-) (adt(2-) = 1,3-azadithiolate, HN(CH2S(-))2) to give the 2:1 adducts [Fe2(xdt)(CO)4(CNBAr3)2](2-). Attempts to prepare the 1:1 adducts [1(BAr3)](2-) (Ar = Ph, C6F5) were unsuccessful, but related 1:1 adducts were obtained using the bulky borane B(C6F4-o-C6F5)3 (BAr(F)*3). By virtue of the N-protection by the borane, salts of [Fe2(pdt)(CO)4(CNBAr3)2](2-) sustain protonation to give hydrides that are stable (in contrast to [H1](-)). The hydrides [H1(BAr3)2](-) are 2.5-5 pKa units more acidic than the parent [H1](-). The adducts [1(BAr3)2](2-) oxidize quasi-reversibly around -0.3 V versus Fc(0/+) in contrast to ca. -0.8 V observed for the [1](2-/-) couple. A simplified synthesis of [1](2-), [3](2-), and [Fe2(pdt)(CO)5(CN)](-) ([2](-)) was developed, entailing reaction of the diiron hexacarbonyl complexes with KCN in MeCN.

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