Impact of genome reduction on bacterial metabolism and its regulation

Science. 2009 Nov 27;326(5957):1263-8. doi: 10.1126/science.1177263.


To understand basic principles of bacterial metabolism organization and regulation, but also the impact of genome size, we systematically studied one of the smallest bacteria, Mycoplasma pneumoniae. A manually curated metabolic network of 189 reactions catalyzed by 129 enzymes allowed the design of a defined, minimal medium with 19 essential nutrients. More than 1300 growth curves were recorded in the presence of various nutrient concentrations. Measurements of biomass indicators, metabolites, and 13C-glucose experiments provided information on directionality, fluxes, and energetics; integration with transcription profiling enabled the global analysis of metabolic regulation. Compared with more complex bacteria, the M. pneumoniae metabolic network has a more linear topology and contains a higher fraction of multifunctional enzymes; general features such as metabolite concentrations, cellular energetics, adaptability, and global gene expression responses are similar, however.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Bacterial Proteins / metabolism*
  • Culture Media
  • Energy Metabolism
  • Enzymes / genetics
  • Enzymes / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial*
  • Genome, Bacterial*
  • Glycolysis
  • Metabolic Networks and Pathways*
  • Mycoplasma pneumoniae / genetics*
  • Mycoplasma pneumoniae / growth & development
  • Mycoplasma pneumoniae / metabolism*
  • RNA, Bacterial / genetics
  • RNA, Bacterial / metabolism
  • Signal Transduction
  • Systems Biology
  • Transcription, Genetic
  • rRNA Operon


  • Bacterial Proteins
  • Culture Media
  • Enzymes
  • RNA, Bacterial
  • Adenosine Triphosphate