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Investigation of the Unusual Ability of the [FeFe] Hydrogenase from Clostridium beijerinckii to Access an O 2 ‐Protected State
Author(s) -
Corrigan Patrick,
Silakov Alexey
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.05403
Subject(s) - hydrogenase , chemistry , oxygen , redox , clostridium beijerinckii , ligand (biochemistry) , enzyme , active site , photochemistry , fourier transform infrared spectroscopy , combinatorial chemistry , biochemistry , inorganic chemistry , organic chemistry , chemical engineering , butanol , receptor , ethanol , engineering
[FeFe] hydrogenases are enzymes capable of rapid interconversion of hydrogen to protons and reducing equivalents. These enzymes are, therefore, a prime target for biotechnological applications such as biochemical fuel cells. Despite their promising nature, these enzymes will never be used in consumer products unless a significant hurdle is overcome: their oxygen sensitivity. In the presence of oxygen, destruction of the various metallocofactors occurs through the generation of reactive oxygen species. One recently discovered [FeFe] hydrogenase, named Cb HydA1, protects itself from oxidative degradation. In this presentation, we characterize this unique enzyme to uncover the underlying reasons for oxygen‐tolerance. To protect itself from oxygen, this enzyme converts to an inactive state (H inact ) in the presence of oxygen and can be readily activate to back under reducing conditions. When in the H inact state we show that this enzyme is stable for long periods of time in air using Fourier transform infrared (FTIR) spectroscopy. We determined through a combination of FTIR experiments and density functional theory calculations that a ligand must bind to an open coordination site in the active site of the enzyme during inactivation. Through spectro‐electrochemical and protein film voltammetry characterizations, we show that this enzyme has a relatively low inactivation/reactivation midpoint potential. We, thus, propose that oxygen‐tolerance is due to a redox process that is concomitant with a ligand binding. These results give us hope that [FeFe] hydrogenases will be used as a powerhouse of renewable energy systems.