O 2 reactions at the six-iron active site (H-cluster) in [FeFe]-hydrogenase
(2011) In Journal of Biological Chemistry 286(47). p.40614-40623- Abstract
Irreversible inhibition by molecular oxygen (O 2) complicates the use of [FeFe]-hydrogenases (HydA) for biotechnological hydrogen (H 2) production. Modification by O 2 of the active site six-iron complex denoted as the H-cluster ([4Fe4S]-2Fe H) of HydA1 from the green alga Chlamydomonas reinhardtii was characterized by x-ray absorption spectroscopy at the iron K-edge. In a time-resolved approach, HydA1 protein samples were prepared after increasing O 2 exposure periods at 0 °C. A kinetic analysis of changes in their x-ray absorption near edge structure and extended X-ray absorption fine structure spectra revealed three phases of O 2 reactions. The first phase (τ... (More)
Irreversible inhibition by molecular oxygen (O 2) complicates the use of [FeFe]-hydrogenases (HydA) for biotechnological hydrogen (H 2) production. Modification by O 2 of the active site six-iron complex denoted as the H-cluster ([4Fe4S]-2Fe H) of HydA1 from the green alga Chlamydomonas reinhardtii was characterized by x-ray absorption spectroscopy at the iron K-edge. In a time-resolved approach, HydA1 protein samples were prepared after increasing O 2 exposure periods at 0 °C. A kinetic analysis of changes in their x-ray absorption near edge structure and extended X-ray absorption fine structure spectra revealed three phases of O 2 reactions. The first phase (τ 1≤4 s) is characterized by the formation of an increased number of Fe-O,C bonds, elongation of the Fe-Fe distance in the binuclear unit (2Fe H), and oxidation of one iron ion. The second phase (τ 2 ≈ 15 s) causes a ∼50% decrease of the number of ∼2.7-ÅFe-Fe distances in the [4Fe4S] subcluster and the oxidation of one more iron ion. The final phase (τ 3 ≤ 1000 s) leads to the disappearance of most Fe-Fe and Fe-S interactions and further iron oxidation. These results favor a reaction sequence, which involves 1) oxygenation at 2Fe H+ leading to the formation of a reactive oxygen species-like superoxide (O 2 -), followed by 2) H-cluster inactivation and destabilization due to ROS attack on the [4Fe4S] cluster to convert it into an apparent [3Fe4S] + unit, leading to 3) complete O 2-induced degradation of the remainders of the H-cluster. This mechanism suggests that blocking of ROS diffusion paths and/or altering the redox potential of the [4Fe4S] cubane by genetic engineering may yield improved O 2tolerance in [FeFe]-hydrogenase.
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- author
- Lambertz, Camilla ; Leidel, Nils ; Havelius, Kajsa G.V. LU ; Noth, Jens ; Chernev, Petko ; Winkler, Martin ; Happe, Thomas and Haumann, Michael
- publishing date
- 2011-11-25
- type
- Contribution to journal
- publication status
- published
- in
- Journal of Biological Chemistry
- volume
- 286
- issue
- 47
- pages
- 10 pages
- publisher
- American Society for Biochemistry and Molecular Biology
- external identifiers
-
- scopus:81755171433
- pmid:21930709
- ISSN
- 0021-9258
- DOI
- 10.1074/jbc.M111.283648
- language
- English
- LU publication?
- no
- id
- 477b040e-c652-454a-897d-fdef7230e3e1
- date added to LUP
- 2020-01-15 10:22:17
- date last changed
- 2024-04-17 03:57:27
@article{477b040e-c652-454a-897d-fdef7230e3e1,
abstract = {{<p>Irreversible inhibition by molecular oxygen (O <sub>2</sub>) complicates the use of [FeFe]-hydrogenases (HydA) for biotechnological hydrogen (H <sub>2</sub>) production. Modification by O <sub>2</sub> of the active site six-iron complex denoted as the H-cluster ([4Fe4S]-2Fe <sub>H</sub>) of HydA1 from the green alga Chlamydomonas reinhardtii was characterized by x-ray absorption spectroscopy at the iron K-edge. In a time-resolved approach, HydA1 protein samples were prepared after increasing O <sub>2</sub> exposure periods at 0 °C. A kinetic analysis of changes in their x-ray absorption near edge structure and extended X-ray absorption fine structure spectra revealed three phases of O <sub>2</sub> reactions. The first phase (τ <sub>1</sub>≤4 s) is characterized by the formation of an increased number of Fe-O,C bonds, elongation of the Fe-Fe distance in the binuclear unit (2Fe <sub>H</sub>), and oxidation of one iron ion. The second phase (τ <sub>2</sub> ≈ 15 s) causes a ∼50% decrease of the number of ∼2.7-ÅFe-Fe distances in the [4Fe4S] subcluster and the oxidation of one more iron ion. The final phase (τ <sub>3</sub> ≤ 1000 s) leads to the disappearance of most Fe-Fe and Fe-S interactions and further iron oxidation. These results favor a reaction sequence, which involves 1) oxygenation at 2Fe <sub>H+</sub> leading to the formation of a reactive oxygen species-like superoxide (O <sub>2</sub> <sup>-</sup>), followed by 2) H-cluster inactivation and destabilization due to ROS attack on the [4Fe4S] cluster to convert it into an apparent [3Fe4S] <sup>+</sup> unit, leading to 3) complete O <sub>2</sub>-induced degradation of the remainders of the H-cluster. This mechanism suggests that blocking of ROS diffusion paths and/or altering the redox potential of the [4Fe4S] cubane by genetic engineering may yield improved O <sub>2</sub>tolerance in [FeFe]-hydrogenase.</p>}},
author = {{Lambertz, Camilla and Leidel, Nils and Havelius, Kajsa G.V. and Noth, Jens and Chernev, Petko and Winkler, Martin and Happe, Thomas and Haumann, Michael}},
issn = {{0021-9258}},
language = {{eng}},
month = {{11}},
number = {{47}},
pages = {{40614--40623}},
publisher = {{American Society for Biochemistry and Molecular Biology}},
series = {{Journal of Biological Chemistry}},
title = {{O <sub>2</sub> reactions at the six-iron active site (H-cluster) in [FeFe]-hydrogenase}},
url = {{http://dx.doi.org/10.1074/jbc.M111.283648}},
doi = {{10.1074/jbc.M111.283648}},
volume = {{286}},
year = {{2011}},
}