Spectroscopic Characterization of the Bridging Amine in the Active Site of [FeFe] Hydrogenase Using Isotopologues of the H-Cluster

Adamska-Venkatesh, Agnieszka, Roy, Souvik, Siebel, Judith F., Simmons, Trevor R., Fontecave, Marc, Artero, Vincent, Reijerse, Edward and Lubitz, Wolfgang (2015) Spectroscopic Characterization of the Bridging Amine in the Active Site of [FeFe] Hydrogenase Using Isotopologues of the H-Cluster. Journal of the American Chemical Society, 137 (40). pp. 12744-12747. ISSN 0002-7863

Full content URL: https://doi.org/10.1021/jacs.5b06240

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Item Type:Article
Item Status:Live Archive

Abstract

The active site of [FeFe] hydrogenase contains a catalytic binuclear iron subsite coordinated by CN– and CO ligands as well as a unique azadithiolate (adt2–) bridging ligand. It has been established that this binuclear cofactor is synthesized and assembled by three maturation proteins HydE, -F, and -G. By means of in vitro maturation in the presence of 15N- and 13C-labeled tyrosine it has been shown that the CN– and CO ligands originate from tyrosine. The source of the bridging adt2– ligand, however, remains unknown. In order to identify the nitrogen of the bridging amine using HYSCORE spectroscopy and distinguish its spectroscopic signature from that of the CN– nitrogens, we studied three isotope-labeled variants of the H-cluster (15N-adt2–/C14N–, 15N-adt2–/C15N–, and 14N-adt2–/C15N–) and extracted accurate values of the hyperfine and quadrupole couplings of both CN– and adt2– nitrogens. This will allow an evaluation of isotopologues of the H-cluster generated by in vitro bioassembly in the presence of various 15N-labeled potential precursors as possible sources of the bridging ligand.

Keywords:Peptides and proteins, Ligands, Precursors, Monomers nitrogen
Subjects:C Biological Sciences > C720 Biological Chemistry
F Physical Sciences > F100 Chemistry
F Physical Sciences > F161 Organometallic Chemistry
Divisions:College of Science > School of Chemistry
ID Code:40680
Deposited On:17 Apr 2020 08:53

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