Metal-ligand cooperativity in the soluble hydrogenase-1 fromPyrococcus furiosus

• Type of Material: Article
• Authors: Gregory E Vansuch, Emory University; Chang-Hao Wu, University of Georgia; Dominik K Haja, University of Georgia; Soshawn A Blair, University of Georgia; Bryant Chica, Emory University; Michael K Johnson, University of Georgia; Michael WW Adams, University of Georgia; Richard Dyer, Emory University
• Language: English
• Date: 2020-08-21
• Publisher: ROYAL SOC CHEMISTRY
• Publication Version: Final Published Version
• Copyright Statement: This journal is © The Royal Society of Chemistry
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1039/d0sc00628a
• Title of Journal or Parent Work: CHEMICAL SCIENCE
• Volume: 11
• Issue: 32
• Start Page: 8572
• End Page: 8581
• Grant/Funding Information: This research was funded by NSF grants DMR1808288 and CHE1807865 (awarded to RBD), grants to MKJ from NIH (R37GM062524) and NSF (MRI CHE1827968) and a grant (DE-FG05-95ER20175 to MWWA) from the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Sciences of the Department of Energy.
• Keywords: CARBON-MONOXIDE; NIFE HYDROGENASES; CATALYTIC CYCLE; RALSTONIA-EUTROPHA; ACTIVE-SITE; Chemistry; PYROCOCCUS-FURIOSUS; Chemistry, Multidisciplinary; Physical Sciences; VULGARIS MIYAZAKI-F; PROTON-TRANSFER; INFRARED-SPECTROSCOPY; ELECTRONIC-STRUCTURE; Science & Technology
• Research Categories: Chemistry, General

Abstract

Metal-ligand cooperativity is an essential feature of bioinorganic catalysis. The design principles of such cooperativity in metalloenzymes are underexplored, but are critical to understand for developing efficient catalysts designed with earth abundant metals for small molecule activation. The simple substrate requirements of reversible proton reduction by the [NiFe]-hydrogenases make them a model bioinorganic system. A highly conserved arginine residue (R355) directly above the exogenous ligand binding position of the [NiFe]-catalytic core is known to be essential for optimal function because mutation to a lysine results in lower catalytic rates. To expand on our studies of soluble hydrogenase-1 from Pyrococcus furiosus (Pf SH1), we investigated the role of R355 by site-directed-mutagenesis to a lysine (R355K) using infrared and electron paramagnetic resonance spectroscopic probes sensitive to active site redox and protonation events. It was found the mutation resulted in an altered ligand binding environment at the [NiFe] centre. A key observation was destabilization of the Nia3+-C state, which contains a bridging hydride. Instead, the tautomeric Nia+-L states were observed. Overall, the results provided insight into complex metal-ligand cooperativity between the active site and protein scaffold that modulates the bridging hydride stability and the proton inventory, which should prove valuable to design principles for efficient bioinspired catalysts. This journal is