Back to Search
Start Over
Tracking the route of molecular oxygen in O2-tolerant membrane-bound [NiFe] hydrogenase.
- Source :
- Proceedings of the National Academy of Sciences of the United States of America; 3/6/2018, Vol. 115 Issue 10, pE2229-E2237, 9p
- Publication Year :
- 2018
-
Abstract
- [NiFe] hydrogenases catalyze the reversible splitting of H<subscript>2</subscript> into protons and electrons at a deeply buried active site. The catalytic center can be accessed by gas molecules through a hydrophobic tunnel network. While most [NiFe] hydrogenases are inactivated by O<subscript>2</subscript>, a small subgroup, including the membrane-bound [NiFe] hydrogenase (MBH) of Ralstonia eutropha, is able to overcome aerobic inactivation by catalytic reduction of O<subscript>2</subscript> to water. This O<subscript>2</subscript>tolerance relies on a special [4Fe3S] cluster that is capable of releasing two electrons upon O<subscript>2</subscript> attack. Here, the O<subscript>2</subscript> accessibility of the MBH gas tunnel network has been probed experimentally using a "soak-and-freeze" derivatization method, accompanied by protein X-ray crystallography and computational studies. This combined approach revealed several sites of O<subscript>2</subscript>molecules within a hydrophobic tunnel network leading, via two tunnel entrances, to the catalytic center of MBH. The corresponding site occupancies were related to the O<subscript>2</subscript> concentrations used for MBH crystal derivatization. The examination of the O<subscript>2</subscript>-derivatized data furthermore uncovered two unexpected structural alterations at the [4Fe3S] cluster, which might be related to the O<subscript>2</subscript>tolerance of the enzyme. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00278424
- Volume :
- 115
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 128512963
- Full Text :
- https://doi.org/10.1073/pnas.1712267115