Oxygen Stability in the New [FeFe]-Hydrogenase from Clostridium beijerinckii SM10 (CbA5H)

Abstract

The newly isolated Clostridium beijerinckii [FeFe]-hydrogenase CbA5H was characterized by Fourier transform infrared spectroscopy coupled to enzymatic activity assays. This showed for the first time that in this enzyme the oxygen-sensitive active state H can be simply and reversibly converted to the oxygen-stable inactive H state. This suggests that oxygen sensitivity is not an intrinsic feature of the catalytic center of [FeFe]-hydrogenases (H-cluster), opening new challenging perspectives on the oxygen sensitivity mechanism as well as new possibilities for exploitation in industrial applications.

O2 sensitivity and H2 production activity of hydrogenases—A review

“…The recently discovered [FeFe] hydrogenase from Clostridium beijerinckii also showed remarkable O 2 insensitivity, recovering the original level of H 2 consumption activity after repeated exposure to air (Morra, Arizzi, Valetti, & Gilardi, ). However, the enzyme still appears to fully lose enzymatic activity in the presence of O 2 and requires reductive reactivation to recuperate the original level of activity.…”

“…U R E 1 (a) Oxygenic inactivation mechanism and the proposed reaction series leading to reversible or irreversible inactivation of (b)[FeFe] and (c)[NiFe] hydrogenases [Color figure can be viewed at wileyonlinelibrary.com] LU AND KOO | 3127 is yet unclear whether or not the higher H 2 production activity will also be true in vivo where electrons are provided biochemically instead of being delivered via an electrode.The recently discovered [FeFe] hydrogenase from Clostridium beijerinckii also showed remarkable O 2 insensitivity, recovering the original level of H 2 consumption activity after repeated exposure to air(Morra, Arizzi, Valetti, & Gilardi, 2016). However, the enzyme still appears to fully lose enzymatic activity in the presence of O 2 and requires reductive reactivation to recuperate the original level of activity.…”

Discovery of novel [FeFe]-hydrogenases for biocatalytic H2-production

“…[9][10][11][12][13] Still, extensive work is needed to obtain sufficient quantities of puried enzyme to perform articial maturation and characterization. As a consequence, only a few [FeFe]-hydrogenases are currently characterized, [11][12][13][14][15][16][17][18] despite the diverse nature of this enzyme family. [19][20][21][22][23] All [FeFe]-hydrogenases feature the central H-domain, containing the aforementioned H-cluster.…”

Redox (In)activations of Metalloenzymes: A Protein Film Voltammetry Approach

“…The formation of these inactive species sometimes has a protective effect. For instance, FeFe hydrogenases, which reversibly oxidize H 2 at a diiron active site, are very O 2 ‐sensitive, but some of them can be purified in an air‐stable, inactive state that regenerates the active enzyme upon reduction. However, in many cases, these inactive species have no reported physiological role.…”