Spectroscopic investigations under whole-cell conditions provide new insight into the metal hydride chemistry of [FeFe]-hydrogenase. Issue 18 (30th April 2020)

• Record Type: Journal Article
• Authors: Mészáros, Lívia S.; Ceccaldi, Pierre; Lorenzi, Marco; Redman, Holly J.; Pfitzner, Emanuel; Heberle, Joachim; Senger, Moritz; Stripp, Sven T.; Berggren, Gustav
• Is Part Of: Chemical science. Volume 11:Issue 18(2020)
• Page Start: 4608
• Page End: 4617
• Publication Date: 2020-04-30
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0sc00512f
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : The mechanism of hydrogen gas formation by [FeFe] hydrogenase is probed under whole cell conditions, revealing the formation of reactive metal hydride species under physiologically relevant conditions. Abstract : Hydrogenases are among the fastest H2 evolving catalysts known to date and have been extensively studied under in vitro conditions. Here, we report the first mechanistic investigation of an [FeFe]-hydrogenase under whole-cell conditions. Functional [FeFe]-hydrogenase from the green alga Chlamydomonas reinhardtii is generated in genetically modified Escherichia coli cells by addition of a synthetic cofactor to the growth medium. The assembly and reactivity of the resulting semi-synthetic enzyme was monitored using whole-cell electron paramagnetic resonance and Fourier-transform Infrared difference spectroscopy as well as scattering scanning near-field optical microscopy. Through a combination of gas treatments, pH titrations, and isotope editing we were able to corroborate the formation of a number of proposed catalytic intermediates in living cells, supporting their physiological relevance. Moreover, a previously incompletely characterized catalytic intermediate is reported herein, attributed to the formation of a protonated metal hydride species.