High sensitivity of human centrin 2 toward radiolytical oxidation: C-terminal tyrosinyl residue as the main target.
Free Radic Biol Med
; 43(2): 216-28, 2007 Jul 15.
Article
em En
| MEDLINE
| ID: mdl-17603931
ABSTRACT
Centrins are calcium-binding proteins that play a significant role in the maintenance of the centrosomal organization, mainly in the continuity between centrosome and microtubular network. Recent data showed that centrosome duplication abnormalities, like overduplication for example, could be due to hydrogen peroxide, suggesting an important impact of oxidative stress. To challenge this hypothesis, we performed one-electron oxidation experiments with human centrin 2, starting from azide radicals. Our results first revealed several intermolecular cross-links generating dimers, tetramers, hexamers, and higher molecular mass species. Dimers result from covalent bond linking the C-terminal tyrosines of each monomer. Second, the methionyl residue at position 19 was oxidized on the monomeric centrin. Further, electron microscopy experiments on centrin 2 showed a preexisting hexameric organization that was stabilized by covalent bonds as a result of irradiation. Overall, these results show that centrin 2 is highly sensitive to ionizing radiation, which could have important consequences on its biological functions.
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Base de dados:
MEDLINE
Assunto principal:
Tirosina
/
Proteínas de Ligação ao Cálcio
/
Proteínas de Ciclo Celular
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article