Different responses of the GlnB and GlnZ proteins upon in vitro uridylylation by the Azospirillum brasilense GlnD protein
Braz. j. med. biol. res
;
41(4): 289-294, Apr. 2008. ilus
Article
Dans Anglais
| LILACS
| ID: lil-479679
ABSTRACT
Azospirillum brasilense is a diazotroph found in association with important agricultural crops. In this organism, the regulation of nitrogen fixation by ammonium ions involves several proteins including the uridylyltransferase/uridylyl-removing enzyme, GlnD, which reversibly uridylylates the two PII proteins, GlnB and GlnZ, in response to the concentration of ammonium ions. In the present study, the uridylylation/deuridylylation cycle of A. brasilense GlnB and GlnZ proteins by GlnD was reconstituted in vitro using the purified proteins. The uridylylation assay was analyzed using non-denaturing polyacrylamide gel electrophoresis and fluorescent protein detection. Our results show that the purified A. brasilense GlnB and GlnZ proteins were uridylylated by the purified A. brasilense GlnD protein in a process dependent on ATP and 2-oxoglutarate. The dependence on ATP for uridylylation was similar for both proteins. On the other hand, at micromolar concentration of 2-oxoglutarate (up to 100 µM), GlnB uridylylation was almost twice that of GlnZ, an effect that was not observed at higher concentrations of 2-oxoglutarate (up to 10 mM). Glutamine inhibited uridylylation and stimulated deuridylylation of both GlnB and GlnZ. However, glutamine seemed to inhibit GlnZ uridylylation more efficiently. Our results suggest that the differences in the uridylylation pattern of GlnB and GlnZ might be important for fine-tuning of the signaling pathway of cellular nitrogen status in A. brasilense.
Texte intégral:
Disponible
Indice:
LILAS (Amériques)
Sujet Principal:
Protéines bactériennes
/
Azospirillum brasilense
Limites du sujet:
Humains
Pays comme sujet:
Amérique du Sud
/
Brésil
langue:
Anglais
Texte intégral:
Braz. j. med. biol. res
Thème du journal:
Biologie
/
Médicament
Année:
2008
Type:
Article
Pays d'affiliation:
Brésil
Institution/Pays d'affiliation:
Universidade Federal do Paraná/BR
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