Studies of propionate toxicity in Salmonella enterica identify 2-methylcitrate as a potent inhibitor of cell growth.
J Biol Chem
; 276(22): 19094-101, 2001 Jun 01.
Article
en En
| MEDLINE
| ID: mdl-11376009
ABSTRACT
Salmonella enterica serovar Typhimurium LT2 showed increased sensitivity to propionate when the 2-methylcitric acid cycle was blocked. A derivative of a prpC mutant (which lacked 2-methylcitrate synthase activity) resistant to propionate was isolated, and the mutation responsible for the newly acquired resistance to propionate was mapped to the citrate synthase (gltA) gene. These results suggested that citrate synthase activity was the source of the increased sensitivity to propionate observed in the absence of the 2-methylcitric acid cycle. DNA sequencing of the wild-type and mutant gltA alleles revealed that the ATG start codon of the wild-type gene was converted to the rare GTG start codon in the revertant strain. This result suggested that lower levels of this enzyme were present in the mutant. Consistent with this change, cell-free extracts of the propionate-resistant strain contained 12-fold less citrate synthase activity. This was interpreted to mean that, in the wild-type strain, high levels of citrate synthase activity were the source of a toxic metabolite. In vitro experiments performed with homogeneous citrate synthase enzyme indicated that this enzyme was capable of synthesizing 2-methylcitrate from propionyl-CoA and oxaloacetate. This result lent further support to the in vivo data, which suggested that citrate synthase was the source of a toxic metabolite.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Propionatos
/
Proteínas Bacterianas
/
Citratos
/
Coenzima A Ligasas
/
Fosfoproteínas Fosfatasas
/
Salmonella enterica
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Biol Chem
Año:
2001
Tipo del documento:
Article
País de afiliación:
Estados Unidos