A soluble form of ammonia monooxygenase in Nitrosomonas europaea
| Autor: | Stefan Gilch, Ortwin Meyer, Ingo Schmidt |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Electrophoresis
Cytochrome Stereochemistry Clinical Biochemistry Inorganic chemistry Nitrosomonas europaea Biochemistry Ammonia chemistry.chemical_compound Hydroxylamine Bacterial Proteins Cytochrome C1 Molecular Biology biology Molecular mass Acetylene Cytochrome c Cell Membrane Electron Spin Resonance Spectroscopy Cytochromes c Ammonia monooxygenase biology.organism_classification Solubility chemistry biology.protein Oxidoreductases Protein Binding |
| Zdroj: | bchm. 390:863-873 |
| ISSN: | 1437-4315 1431-6730 |
| Popis: | Ammonia monooxygenase (AMO) of Nitrosomonas europaea is a metalloenzyme that catalyzes the oxidation of ammonia to hydroxylamine. This study shows that AMO resides in the cytoplasm of the bacteria in addition to its location in the membrane and is distributed approximately equally in both subcellular fractions. AMO in both fractions catalyzes the oxidation of ammonia and binds [14C]acetylene, a mechanism-based inhibitor which specifically interacts with catalytically active AMO. Soluble AMO was purified 12-fold to electrophoretic homogeneity with a yield of 8%. AMO has a molecular mass of approximately 283 kDa with subunits of ca. 27 kDa (α-subunit, AmoA), ca. 42 kDa (β-subunit, AmoB), and ca. 24 kDa (γ-subunit, cytochrome c 1) in an α3β3γ3 sub-unit structure. Different from the β-subunit of membrane-bound AMO, AmoB of soluble AMO possesses an N-terminal signal sequence. AMO contains Cu (9.4±0.6 mol per mol AMO), Fe (3.9±0.3 mol per mol AMO), and Zn (0.5 to 2.6 mol per mol AMO). Upon reduction the visible absorption spectrum of AMO reveals absorption bands characteristic of cytochrome c. Electron para-magnetic resonance spectroscopy of air-oxidized AMO at 50 K shows a paramagnetic signal originating from Cu2+ and at 10 K a paramagnetic signal characteristic of heme-Fe. |
| Databáze: | OpenAIRE |
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