Format

Send to

Choose Destination
PLoS One. 2015 Jul 17;10(7):e0133118. doi: 10.1371/journal.pone.0133118. eCollection 2015.

Identification of an Isothiocyanate on the HypEF Complex Suggests a Route for Efficient Cyanyl-Group Channeling during [NiFe]-Hydrogenase Cofactor Generation.

Author information

1
Department of Physics, Freie Universität Berlin, Berlin, Germany.
2
Institute of Microbiology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany.

Abstract

[NiFe]-hydrogenases catalyze uptake and evolution of H2 in a wide range of microorganisms. The enzyme is characterized by an inorganic nickel/ iron cofactor, the latter of which carries carbon monoxide and cyanide ligands. In vivo generation of these ligands requires a number of auxiliary proteins, the so-called Hyp family. Initially, HypF binds and activates the precursor metabolite carbamoyl phosphate. HypF catalyzes removal of phosphate and transfers the carbamate group to HypE. In an ATP-dependent condensation reaction, the C-terminal cysteinyl residue of HypE is modified to what has been interpreted as thiocyanate. This group is the direct precursor of the cyanide ligands of the [NiFe]-hydrogenase active site cofactor. We present a FT-IR analysis of HypE and HypF as isolated from E. coli. We follow the HypF-catalyzed cyanation of HypE in vitro and screen for the influence of carbamoyl phosphate and ATP. To elucidate on the differences between HypE and the HypEF complex, spectro-electrochemistry was used to map the vibrational Stark effect of naturally cyanated HypE. The IR signature of HypE could ultimately be assigned to isothiocyanate (-N=C=S) rather than thiocyanate (-S-C≡N). This has important implications for cyanyl-group channeling during [NiFe]-hydrogenase cofactor generation.

PMID:
26186649
PMCID:
PMC4506123
DOI:
10.1371/journal.pone.0133118
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Public Library of Science Icon for PubMed Central
Loading ...
Support Center