Bacterial microcompartments: their properties and paradoxes

Bioessays. 2008 Nov;30(11-12):1084-95. doi: 10.1002/bies.20830.


Many bacteria conditionally express proteinaceous organelles referred to here as microcompartments (Fig. 1). These microcompartments are thought to be involved in a least seven different metabolic processes and the number is growing. Microcompartments are very large and structurally sophisticated. They are usually about 100-150 nm in cross section and consist of 10,000-20,000 polypeptides of 10-20 types. Their unifying feature is a solid shell constructed from proteins having bacterial microcompartment (BMC) domains. In the examples that have been studied, the microcompartment shell encases sequentially acting metabolic enzymes that catalyze a reaction sequence having a toxic or volatile intermediate product. It is thought that the shell of the microcompartment confines such intermediates, thereby enhancing metabolic efficiency and/or protecting cytoplasmic components. Mechanistically, however, this creates a paradox. How do microcompartments allow enzyme substrates, products and cofactors to pass while confining metabolic intermediates in the absence of a selectively permeable membrane? We suggest that the answer to this paradox may have broad implications with respect to our understanding of the fundamental properties of biological protein sheets including microcompartment shells, S-layers and viral capsids.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Bacteria / metabolism*
  • Bacteria / ultrastructure
  • Bacterial Physiological Phenomena
  • Bacterial Proteins / chemistry
  • Carbon Dioxide / chemistry
  • Kinetics
  • Microscopy, Electron
  • Models, Biological
  • Molecular Conformation
  • Organelles / chemistry
  • Oxygen / chemistry
  • Peptides / chemistry
  • Permeability
  • Proteins / chemistry
  • Salmonella / metabolism


  • Bacterial Proteins
  • Peptides
  • Proteins
  • Carbon Dioxide
  • Oxygen