Oxidized NADH oxidase inhibits activity of an ATP/NAD kinase from a Thermophilic archaeon.
Protein J
; 29(8): 609-16, 2010 Nov.
Article
em En
| MEDLINE
| ID: mdl-21082227
ABSTRACT
NADH oxidases (NOXs) are important enzymes in detoxifying oxidative stress and regenerating oxidized pyridine nucleotides. In the present study, a NOX from Thermococcus kodakarensis KOD1 (NOXtk) was recombinantly expressed in Escherichia coli and purified to homogeneity. NOXtk displayed NADH oxidase activity that was inhibited by oxidization. Under physiological conditions, unoxidized and oxidized NOXtk formed dimers and hexamers, respectively. Mutating the single cysteine residue Cys45 to alanine (NOXtkC45A) decreased NADH oxidase activity without affecting dimerization or hexamerization, suggesting that oligomerization does not occur through disulfide bond formation. Pull-down assay results indicated that an ATP/NAD kinase from T. kodakarensis KOD1 (ANKtk) binds to NOXtk. Use of several assays revealed that ANKtk can only bind to oxidized hexameric NOXtk, through which it inhibits ANKtk activity. Because ANKtk converts NADH to NADPH (an important factor in oxidative stress protection), a model based on in vitro result was proposed in which NOXtk hexamerization under oxic conditions inhibits both NOXtk and ANKtk activities, thereby sensitizing cells to oxidative stress-induced death.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxigênio
/
Fosfotransferases (Aceptor do Grupo Fosfato)
/
Fosfotransferases (Aceptor do Grupo Álcool)
/
Thermococcus
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Proteínas Arqueais
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Complexos Multienzimáticos
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NADH NADPH Oxirredutases
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Protein J
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
China