Details

Autor(en) / Beteiligte

• Reijerse, Edward J
• Pham, Cindy C
• Pelmenschikov, Vladimir
• Gilbert-Wilson, Ryan
• Adamska-Venkatesh, Agnieszka
• Siebel, Judith F
• Gee, Leland B
• Yoda, Yoshitaka
• Tamasaku, Kenji
• Lubitz, Wolfgang
• Rauchfuss, Thomas B
• Cramer, Stephen P

Titel

Direct Observation of an Iron-Bound Terminal Hydride in [FeFe]-Hydrogenase by Nuclear Resonance Vibrational Spectroscopy

Ist Teil von

• Journal of the American Chemical Society, 2017-03, Vol.139 (12), p.4306-4309

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2017

Quelle

MEDLINE

Beschreibungen/Notizen

• [FeFe]-hydrogenases catalyze the reversible reduction of protons to molecular hydrogen with extremely high efficiency. The active site (“H-cluster”) consists of a [4Fe–4S]H cluster linked through a bridging cysteine to a [2Fe]H subsite coordinated by CN– and CO ligands featuring a dithiol-amine moiety that serves as proton shuttle between the protein proton channel and the catalytic distal iron site (Fed). Although there is broad consensus that an iron-bound terminal hydride species must occur in the catalytic mechanism, such a species has never been directly observed experimentally. Here, we present FTIR and nuclear resonance vibrational spectroscopy (NRVS) experiments in conjunction with density functional theory (DFT) calculations on an [FeFe]-hydrogenase variant lacking the amine proton shuttle which is stabilizing a putative hydride state. The NRVS spectra unequivocally show the bending modes of the terminal Fe–H species fully consistent with widely accepted models of the catalytic cycle.