Dataset Information

Cyanide Binding to [FeFe]-Hydrogenase Stabilizes the Alternative Configuration of the Proton Transfer Pathway.

ABSTRACT: Hydrogenases are H₂ converting enzymes that harbor catalytic cofactors in which iron (Fe) ions are coordinated by biologically unusual carbon monoxide (CO) and cyanide (CN^- ) ligands. Extrinsic CO and CN^- , however, inhibit hydrogenases. The mechanism by which CN^- binds to [FeFe]-hydrogenases is not known. Here, we obtained crystal structures of the CN^- -treated [FeFe]-hydrogenase CpI from Clostridium pasteurianum. The high resolution of 1.39 Å allowed us to distinguish intrinsic CN^- and CO ligands and to show that extrinsic CN^- binds to the open coordination site of the cofactor where CO is known to bind. In contrast to other inhibitors, CN^- treated crystals show conformational changes of conserved residues within the proton transfer pathway which could allow a direct proton transfer between E279 and S319. This configuration has been proposed to be vital for efficient proton transfer, but has never been observed structurally.

SUBMITTER: Duan J

PROVIDER: S-EPMC10107461 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cyanide Binding to [FeFe]-Hydrogenase Stabilizes the Alternative Configuration of the Proton Transfer Pathway.

Duan Jifu J Hemschemeier Anja A Burr David J DJ Stripp Sven T ST Hofmann Eckhard E Happe Thomas T

Angewandte Chemie (International ed. in English) 20230110 7

Hydrogenases are H2 converting enzymes that harbor catalytic cofactors in which iron (Fe) ions are coordinated by biologically unusual carbon monoxide (CO) and cyanide (CN- ) ligands. Extrinsic CO and CN- , however, inhibit hydrogenases. The mechanism by which CN- binds to [FeFe]-hydrogenases is not known. Here, we obtained crystal structures of the CN- -treated [FeFe]-hydrogenase CpI from Clostridium pasteurianum. The high resolution of 1.3 ...[more]

PMID: 36464641

Similar Datasets

Project description:[FeFe] hydrogenases, metalloenzymes catalyzing proton/dihydrogen interconversion, have attracted intense attention due to their remarkable catalytic properties and (bio-)technological potential for a future hydrogen economy. In order to unravel the factors enabling their efficient catalysis, both their unique organometallic cofactors and protein structural features, i.e., "outer-coordination sphere" effects have been intensively studied. These structurally diverse enzymes are divided into distinct phylogenetic groups, denoted as Group A-D. Prototypical Group A hydrogenases display high turnover rates (104-105 s-1). Conversely, the sole characterized Group D representative, Thermoanaerobacter mathranii HydS (TamHydS), shows relatively low catalytic activity (specific activity 10-1 μmol H2 mg-1 min-1) and has been proposed to serve a H2-sensory function. The various groups of [FeFe] hydrogenase share the same catalytic cofactor, the H-cluster, and the structural factors causing the diverging reactivities of Group A and D remain to be elucidated. In the case of the highly active Group A enzymes, a well-defined proton transfer pathway (PTP) has been identified, which shuttles H+ between the enzyme surface and the active site. In Group D hydrogenases, this conserved pathway is absent. Here, we report on the identification of highly conserved amino acid residues in Group D hydrogenases that constitute a possible alternative PTP. We varied two proposed key amino acid residues of this pathway (E252 and E289, TamHydS numbering) via site-directed mutagenesis and analyzed the resulting variants via biochemical and spectroscopic methods. All variants displayed significantly decreased H2-evolution and -oxidation activities. Additionally, the variants showed two redox states that were not characterized previously. These findings provide initial evidence that these amino acid residues are central to the putative PTP of Group D [FeFe] hydrogenase. Since the identified residues are highly conserved in Group D exclusively, our results support the notion that the PTP is not universal for different phylogenetic groups in [FeFe] hydrogenases.

Dataset Information

Cyanide Binding to [FeFe]-Hydrogenase Stabilizes the Alternative Configuration of the Proton Transfer Pathway.

Publications

Cyanide Binding to [FeFe]-Hydrogenase Stabilizes the Alternative Configuration of the Proton Transfer Pathway.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets