Functional identification of novel genes involved in the glutathione-independent gentisate pathway in Corynebacterium glutamicum

Appl Environ Microbiol. 2005 Jul;71(7):3442-52. doi: 10.1128/AEM.71.7.3442-3452.2005.


Corynebacterium glutamicum used gentisate and 3-hydroxybenzoate as its sole carbon and energy source for growth. By genome-wide data mining, a gene cluster designated ncg12918-ncg12923 was proposed to encode putative proteins involved in gentisate/3-hydroxybenzoate pathway. Genes encoding gentisate 1,2-dioxygenase (ncg12920) and fumarylpyruvate hydrolase (ncg12919) were identified by cloning and expression of each gene in Escherichia coli. The gene of ncg12918 encoding a hypothetical protein (Ncg12918) was proved to be essential for gentisate-3-hydroxybenzoate assimilation. Mutant strain RES167Deltancg12918 lost the ability to grow on gentisate or 3-hydroxybenzoate, but this ability could be restored in C. glutamicum upon the complementation with pXMJ19-ncg12918. Cloning and expression of this ncg12918 gene in E. coli showed that Ncg12918 is a glutathione-independent maleylpyruvate isomerase. Upstream of ncg12920, the genes ncg12921-ncg12923 were located, which were essential for gentisate and/or 3-hydroxybenzoate catabolism. The Ncg12921 was able to up-regulate gentisate 1,2-dioxygenase, maleylpyruvate isomerase, and fumarylpyruvate hydrolase activities. The genes ncg12922 and ncg12923 were deduced to encode a gentisate transporter protein and a 3-hydroxybenzoate hydroxylase, respectively, and were essential for gentisate or 3-hydroxybenzoate assimilation. Based on the results obtained in this study, a GSH-independent gentisate pathway was proposed, and genes involved in this pathway were identified.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • Cloning, Molecular
  • Corynebacterium glutamicum / enzymology*
  • Corynebacterium glutamicum / genetics
  • Corynebacterium glutamicum / metabolism
  • Dioxygenases / genetics
  • Dioxygenases / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Bacterial
  • Gentisates / metabolism*
  • Glutathione / metabolism*
  • Hydrolases / genetics
  • Hydrolases / metabolism
  • Hydroxybenzoates / metabolism
  • Multigene Family
  • cis-trans-Isomerases / genetics
  • cis-trans-Isomerases / metabolism


  • Bacterial Proteins
  • Gentisates
  • Hydroxybenzoates
  • 3-hydroxybenzoic acid
  • Dioxygenases
  • gentisate 1,2-dioxygenase
  • Hydrolases
  • fumarylpyruvate hydrolase
  • cis-trans-Isomerases
  • maleylpyruvate isomerase
  • Glutathione