Citrate synthase and 2-methylcitrate synthase: structural, functional and evolutionary relationships

Microbiology (Reading). 1998 Apr;144 ( Pt 4):929-35. doi: 10.1099/00221287-144-4-929.


Following the complete sequencing of the Escherichia coli genome, it has been shown that the proposed second citrate synthase of this organism, recently described by the authors, is in fact a 2-methylcitrate synthase that possesses citrate synthase activity as a minor component. Whereas the hexameric citrate synthase is constitutively produced, the 2-methylcitrate synthase is induced during growth on propionate, and the catabolism of propionate to succinate and pyruvate via 2-methylcitrate is proposed. The citrate synthases of the psychrotolerant eubacterium DS2-3R, and of the thermophilic archaea Thermoplasma acidophilum and Pyrococcus furiosus, are approximately 40% identical in sequence to the Escherichia coli 2-methylcitrate synthase and also possess 2-methylcitrate synthase activity. The data are discussed with respect to the structure, function and evolution of citrate synthase and 2-methylcitrate synthase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism
  • Citrate (si)-Synthase / genetics*
  • Citrate (si)-Synthase / isolation & purification
  • Citrate (si)-Synthase / metabolism
  • Escherichia coli / enzymology*
  • Escherichia coli / growth & development
  • Genes, Bacterial*
  • Oxo-Acid-Lyases / analysis
  • Oxo-Acid-Lyases / genetics*
  • Oxo-Acid-Lyases / isolation & purification
  • Oxo-Acid-Lyases / metabolism


  • Bacterial Proteins
  • Citrate (si)-Synthase
  • 2-methylcitrate synthase
  • Oxo-Acid-Lyases