The activation of the [NiFe]-hydrogenase from Allochromatium vinosum. An infrared spectro-electrochemical study
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- 作者：Boris Bleijlevens ; Fleur A. van Broekhuizen ; Antonio L. De Lacey ; Winfried Roseboom ; Victor M. Fernandez and Simon P. J. Albracht
- 关键词：[NiFe] ; hydrogenase ; Infrared spectroscopy ; Redox titrations ; Activation ; Allochromatium vinosum
- 刊名：Journal of Biological Inorganic Chemistry
- 出版年：2004
- 出版时间：September 2004
- 年：2004
- 卷：9
- 期：6
- 页码：743-752
- 全文大小：348 KB
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Life Sciences
Biochemistry
Microbiology - 出版者：Springer Berlin / Heidelberg
- ISSN：1432-1327
文摘
The membrane-bound [NiFe]-hydrogenase from Allochromatium vinosum can occur in several inactive or active states. This study presents the first systematic infrared characterisation of the A. vinosum enzyme, with emphasis on the spectro-electrochemical properties of the inactive/active transition. This transition involves an energy barrier, which can be overcome at elevated temperatures. The reduced Ready enzyme can exist in two different inactive states, which are in an apparent acid–base equilibrium. It is proposed that a hydroxyl ligand in a bridging position in the Ni-Fe site is protonated and that the formed water molecule is subsequently removed. This enables the active site to bind hydrogen in a bridging position, allowing the formation of the fully active state of the enzyme. It is further shown that the active site in enzyme reduced by 1 bar H2 can occur in three different electron paramagnetic resonance (EPR)-silent states with a different degree of protonation.