Aspergillus oryzae flavohemoglobins promote oxidative damage by hydrogen peroxide.
Biochem Biophys Res Commun
; 394(3): 558-61, 2010 Apr 09.
Article
em En
| MEDLINE
| ID: mdl-20211603
ABSTRACT
Apart from their well-established role in nitric oxide detoxification, flavohemoglobins (FHbs) are also believed to be involved in protection against oxidative stress in some yeast and bacteria. However, different studies have reported contradictory results in this regard. Here, we investigate the relationship between two FHbs in Aspergillus oryzae (cytosolic FHb1 and mitochondrial FHb2) and oxidative stress. The strains deficient in the two FHbs exhibited higher resistance to hydrogen peroxide than the wild-type. In addition, the FHb2 overexpression strain showed hypersensitivity to hydrogen peroxide. Flavin reductase accompanied by the ferric reductase activities of the two FHbs were observed in correspondence with this expression. The reductase activities of the FHbs were attributed to their C-terminal flavin reductase domains. The reduced intracellular free iron can subsequently promote oxidative damage by accelerating the Fenton reaction in the cytosol and mitochondria (corresponding to the subcellular localizations of the two FHbs). This study is the first to show that fungal FHbs have a deleterious effect on oxidative protection, and suggests that the accelerated Fenton reaction induced by FHbs might be responsible for this effect.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Aspergillus oryzae
/
Estresse Oxidativo
/
Hemeproteínas
Idioma:
En
Revista:
Biochem Biophys Res Commun
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Japão