Polyphosphate accumulation and oxidative DNA damage in superoxide dismutase-deficient Escherichia coli.
Free Radic Biol Med
; 31(11): 1352-9, 2001 Dec 01.
Article
en En
| MEDLINE
| ID: mdl-11728806
Inorganic polyphosphate is a ubiquitous, linear polymer of phosphate residues linked by high-energy phosphoanhydride bonds. In response to starvation, polyP levels are increased up to 100-fold. It has been proposed that chelation of transition metals by polyP might reduce their toxicity, and that polyP accumulation is vital for survival in stationary phase. SOD-deficient E. coli is unable to survive in stationary phase. We found that deletion of the cytoplasmic SODs does not impair the cell's capability of synthesizing polyP. However, transient accumulation of polyphosphate correlated with increased resistance to H(2)O(2) and protection of DNA against oxidative damage. The reason for this protective effect of polyP is the induction of HPII catalase and DNA repair enzymes as members of the rpoS regulon. PolyP did not directly protect DNA against oxidative damage in vitro and acted as a pro-oxidant by stimulating the production of hydroxyl radical in the Fenton reaction. It is thus suggested that accumulation of poly P and rpoS induction cannot compensate for the lack of cytosolic SODs for survival in stationary phase.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Polifosfatos
/
Superóxido Dismutasa
/
Daño del ADN
/
Estrés Oxidativo
/
Escherichia coli
Idioma:
En
Revista:
Free Radic Biol Med
Asunto de la revista:
BIOQUIMICA
/
MEDICINA
Año:
2001
Tipo del documento:
Article
País de afiliación:
Kuwait
Pais de publicación:
Estados Unidos