Taming of a Poison: Biosynthesis of the NiFe-Hydrogenase Cyanide Ligands

  title={Taming of a Poison: Biosynthesis of the NiFe-Hydrogenase Cyanide Ligands},
  author={Stefanie Reissmann and Elisabeth O. Hochleitner and Haofan Wang and Athanasios Paschos and Friedrich Lottspeich and Richard S. Glass and August B{\"o}ck},
  pages={1067 - 1070}
NiFe-hydrogenases have an Ni-Fe site in which the iron has one CO and two CN groups as ligands. Synthesis of the CN ligands requires the activity of two hydrogenase maturation proteins: HypF and HypE. HypF is a carbamoyltransferase that transfers the carbamoyl moiety of carbamoyladenylate to the COOH-terminal cysteine of HypE and thus forms an enzyme-thiocarbamate. HypE dehydrates theS-carbamoyl moiety in an adenosine triphosphate–dependent process to yield the enzyme thiocyanate. Chemical… 
[NiFe]‐Hydrogenase Cofactor Assembly
Heterodimeric [NiFe]-hydrogenases catalyze the activation of dihydrogen. The large subunit of all [NiFe]-hydrogenases studied to date harbors a bimetallic catalytic center comprising a nickel ion and
Crystal structures of the carbamoylated and cyanated forms of HypE for [NiFe] hydrogenase maturation
These structures reveal the detailed interactions around the carbamoylated and cyanated cysteine, providing structural basis for the biological conversion of primary amide to nitrile, and suggest that Lys134 functions as a proton acceptor in the dehydration of thiocarboxamide.
Carbamoylphosphate serves as the source of CN−, but not of the intrinsic CO in the active site of the regulatory [NiFe]‐hydrogenase from Ralstonia eutropha
Infrared spectroscopy of purified hydrogenase provided direct evidence that only the cyanide ligands, but not the CO ligand, originate from CO2 and carbamoylphosphate, and incorporation of label from 13CO exclusively into the carbonyl ligand indicates that free CO is a possible precursor in carbonyL ligand biosynthesis.
The Influence of Oxygen on [NiFe]–Hydrogenase Cofactor Biosynthesis and How Ligation of Carbon Monoxide Precedes Cyanation
An FT–IR spectroscopic analysis of HypC–HypD isolated from a hydrogenase–competent wild–type strain of Escherichia coli suggests that CO ligation precedes cyanation in vivo, and provides a rationale for the deleterious effects of O2 on in vivo cofactor biosynthesis.
Identification of an Isothiocyanate on the HypEF Complex Suggests a Route for Efficient Cyanyl–Group Channeling during [NiFe]–Hydrogenase Cofactor Generation
The IR signature of HypE could ultimately be assigned to isothiocyanate (–N=C=S) rather than thiOCyanate(–S–C≡N), which has important implications for cyanyl–group channeling during [NiFe]–hydrogenase cofactor generation.
Formyltetrahydrofolate decarbonylase synthesizes the active site CO ligand of O2-tolerant [NiFe] hydrogenase.
In vitro evidence is presented that purified HypX first transfers the formyl group of N10-formyltetrahydrofolate to produce formyl-coenzyme A (formyl-CoA) as central reaction intermediate, which makes it a unique catalyst among the group of CO-releasing enzymes.
The complex between hydrogenase-maturation proteins HypC and HypD is an intermediate in the supply of cyanide to the active site iron of [NiFe]-hydrogenases.
The results suggest the existence of a dynamic complex between the hydrogenase maturation proteins HypD, HypC, HypE and HypF, which is the site of ligand biosynthesis and attachment to the iron atom of the NiFe site in hydrogenase 3.
Probing the Origin of the Metabolic Precursor of the CO Ligand in the Catalytic Center of [NiFe] Hydrogenase*
The results indicate at least two different pathways for biosynthesis of the CO ligand of [NiFe] hydrogenase, and the data indicate multiple, growth mode-dependent biosynthetic pathways for the carbonyl ligand.
[NiFe]-Hydrogenase Maturation.
Recent work illuminating how the accessory proteins contribute to the maturation of [NiFe]-hydrogenase is reviewed and some of the outstanding questions that remain to be resolved are discussed.
The importance of iron in the biosynthesis and assembly of [NiFe]-hydrogenases
Genetic analyses have provided evidence for the existence of key checkpoints during cofactor biosynthesis and enzyme assembly that ensure correct spatiotemporal maturation of these modular oxidoreductases.


HypF, a Carbamoyl Phosphate-converting Enzyme Involved in [NiFe] Hydrogenase Maturation*
Extensive mutagenesis of the putative functional motifs deduced from the derived amino acid sequence showed a full correlation of the resulting variants between their activity in hydrogenase maturation and the in vitro reactivity with carbamoyl phosphate.
Metal insertion into NiFe-hydrogenases.
The synthesis and the insertion of the metallocentre of NiFe-hydrogenases is a complex process, in which seven maturation enzymes plus ATP, GTP and carbamoyl phosphate are involved and a pathway along which maturation may take place is proposed.
Classification and phylogeny of hydrogenases.
Compelling evidence from sequences and structures indicates that the [NiFe]- and [Fe]-H2ases are phylogenetically distinct classes of proteins, which would be consistent with the phylogenetic distinctiveness of the two classes of H2ases.
Urea cycle: chemical simulation of arginine biosynthesis
We have successfully simulated the salient features of the urea cycle. In this effort an appropriately protected ornithine was transformed to citrulline, via use of a novel amide transfer reagent;
X-ray crystal structure of aminoimidazole ribonucleotide synthetase (PurM), from the Escherichia coli purine biosynthetic pathway at 2.5 A resolution.
The first structure of a new class of ATP-binding enzyme, PurM, has been solved and a model for the active site has been proposed, which is unprecedented, with an extensive and unusual sheet-mediated intersubunit interaction defining the active-site grooves.
Responses of the Fe(CN)2(CO) Unit to Electronic Changes as Related to Its Role in [NiFe]Hydrogenase
The observation of nearly identical infrared spectra in the diatomic (2000 cm-1) region of oxidized forms of [NiFe]hydrogenases, as isolated from Chromatium vinosum (Happe et al. Nature 1997, 385,
Thiocyanate biosynthesis in the tropical marine sponge Axinyssa n. sp.
The biosynthetic origin of the thiocyanate carbon in 2- thiocyanatoneopupukeanane (1) is defined by incorporation of sodium [C] cyanide and [C] thiocyanate into Axinyssa n.sp. The specificity of
Reactivity of cationic isocyanide iron(II) derivatives towards nucleophilic agents
Abstract Attack of MeNH 2 on two adjacent isocyanide ligands in [Fe(dppe)(CNPh) 4 ](ClO 4 ) 2 (Ia) gives (II). II reacts with concentrated aqueous HClO 4 to give (III), which contains a chelating
Novel marine sponge derived amino acids 13. Additional psammaplin derivatives from Psammaplysilla purpurea
Abstract An investigation of a sponge rich in psammaplin derivatives provides some insight into the biogenesis of this group of amino acid derivatives. Accompanying psammaplin A (1) were a new