Biochemical and spectroscopic characterization of the membrane-bound nitrate reductase from Marinobacter hydrocarbonoclasticus 617

Autor: Guy Fauque, Jorge Lampreia, Cristina Correia, Carlos D. Brondino, José J. G. Moura, Isabel Moura, Stéphane Besson, Pablo J. González
Přispěvatelé: Departamento de Quimica (REQUIMTE), Universidade de Lisboa (ULISBOA)-Centro de Quimica Fina e Biotecnologia, Facultad de Bioquímica y Ciencias Biológicas [Santa Fe] (FBCB), Universidad Nacional del Litoral [Santa Fe] (UNL), Laboratoire de Microbiologie et Biotechnologie des Environnements Chauds, Université de la Méditerranée - Aix-Marseille 2-Université de Provence - Aix-Marseille 1, Universidade de Lisboa = University of Lisbon (ULISBOA)-Centro de Quimica Fina e Biotecnologia
Rok vydání: 2008
Předmět:
MESH: Oxidation-Reduction
Enzyme complex
MESH: Alteromonadaceae: enzymology
MESH: Hydrogen-Ion Concentration
MESH: Electrophoresis
01 natural sciences
Biochemistry
MESH: Guanine Nucleotides: analysis
chemistry
metabolism
Nitrate Reductase
law.invention
chemistry.chemical_compound
Nitrate
law
MESH: Spectrophotometry
Ultraviolet
Marinobacter hydrocarbonoclasticus
Electron paramagnetic resonance
0303 health sciences
biology
Chemistry
MESH: Molecular Weight
Alteromonadaceae
MESH: Pterins: analysis
chemistry
metabolism
Temperature
MESH: Molybdenum: chemistry
metabolism
Hydrogen-Ion Concentration
MESH: Temperature
Guanine Nucleotides
[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry
Molecular Biology/Biomolecules [q-bio.BM]
Oxidation-Reduction
MESH: Cell Membrane: metabolism
Electrophoresis
Stereochemistry
Iron
Inorganic chemistry
Heme
010402 general chemistry
Nitrate reductase
MESH: Iron: chemistry
metabolism
MESH: Potentiometry
Inorganic Chemistry
03 medical and health sciences
[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry
Molecular Biology/Biochemistry [q-bio.BM]
030304 developmental biology
Molybdenum
MESH: Nitrate Reductase: analysis
chemistry
metabolism
Cell Membrane
Molybdopterin
Electron Spin Resonance Spectroscopy
biology.organism_classification
0104 chemical sciences
MESH: Heme: chemistry
metabolism
Pterins
Heme C
Molecular Weight
Heme B
Potentiometry
MESH: Electron Spin Resonance Spectroscopy
Spectrophotometry
Ultraviolet
Zdroj: Journal of Biological Inorganic Chemistry
Journal of Biological Inorganic Chemistry, Springer Verlag, 2008, 13 (8), pp.1321-33. ⟨10.1007/s00775-008-0416-1⟩
ISSN: 0949-8257
1432-1327
DOI: 10.1007/s00775-008-0416-1⟩
Popis: Membrane-bound nitrate reductase from Marinobacter hydrocarbonoclasticus 617 can be solubilized in either of two ways that will ultimately determine the presence or absence of the small (Iota) subunit. The enzyme complex (NarGHI) is composed of three subunits with molecular masses of 130, 65, and 20 kDa. This enzyme contains approximately 14 Fe, 0.8 Mo, and 1.3 molybdopterin guanine dinucleotides per enzyme molecule. Curiously, one heme b and 0.4 heme c per enzyme molecule have been detected. These hemes were potentiometrically characterized by optical spectroscopy at pH 7.6 and two noninteracting species were identified with respective midpoint potentials at Em=+197 mV (heme c) and -4.5 mV (heme b). Variable-temperature (4-120 K) X-band electron paramagnetic resonance (EPR) studies performed on both as-isolated and dithionite-reduced nitrate reductase showed, respectively, an EPR signal characteristic of a [3Fe-4S]+ cluster and overlapping signals associated with at least three types of [4Fe-4S]+ centers. EPR of the as-isolated enzyme shows two distinct pH-dependent Mo(V) signals with hyperfine coupling to a solvent-exchangeable proton. These signals, called "low-pH" and "high-pH," changed to a pH-independent Mo(V) signal upon nitrate or nitrite addition. Nitrate addition to dithionite-reduced samples at pH 6 and 7.6 yields some of the EPR signals described above and a new rhombic signal that has no hyperfine structure. The relationship between the distinct EPR-active Mo(V) species and their plausible structures is discussed on the basis of the structural information available to date for closely related membrane-bound nitrate reductases.
Databáze: OpenAIRE
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