Abstract
Escherichia coli synthesizes three selenocysteine-dependent formate dehydrogenases (Fdh) that also have a molybdenum cofactor. Fdh-H couples formate oxidation with proton reduction in the formate hydrogenlyase (FHL) complex. The activity of Fdh-H in solution can be measured with artificial redox dyes but, unlike Fdh-O and Fdh-N, it has never been observed by chromogenic activity staining after non-denaturing polyacrylamide gel electrophoresis (PAGE). Here, we demonstrate that Fdh-H activity is present in extracts of cells from stationary phase cultures and forms a single, fast-migrating species. The activity is oxygen labile during electrophoresis explaining why it has not been previously observed as a discreet activity band. The appearance of Fdh-H activity was dependent on an active selenocysteine incorporation system, but was independent of the [NiFe]-hydrogenases (Hyd), 1, 2 or 3. We also identified new active complexes of Fdh-N and Fdh-O during fermentative growth. The findings of this study indicate that Fdh-H does not form a strong complex with other Fdh or Hyd enzymes, which is in line with it being able to deliver electrons to more than one redox-active enzyme complex.
Original language | English |
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Pages (from-to) | 62-67 |
Number of pages | 6 |
Journal | Biochemistry and Biophysics Reports |
Volume | 1 |
Issue number | 1 |
DOIs | |
Publication status | Published - May 2015 |
Keywords
- Chromogenic activity staining
- Enzyme complexes
- Formate dehydrogenase H
- Stationary phase
- [NiFe]-hydrogenase
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Cell Biology
- Molecular Biology