Carboxysomes: cyanobacterial RubisCO comes in small packages

Photosynth Res. 2011 Sep;109(1-3):7-20. doi: 10.1007/s11120-011-9656-y. Epub 2011 May 10.

Abstract

Cyanobacteria (as well as many chemoautotrophs) actively pump inorganic carbon (in the form of HCO(3)(-)) into the cytosol in order to enhance the overall efficiency of carbon fixation. The success of this approach is dependent upon the presence of carboxysomes-large, polyhedral, cytosolic bodies which sequester ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) and carbonic anhydrase. Carboxysomes seem to function by allowing ready passage of HCO(3)(-) into the body, but hindering the escape of evolved CO(2), promoting the accumulation of CO(2) in the vicinity of RubisCO and, consequently, efficient carbon fixation. This selectivity is mediated by a thin shell of protein, which envelops the carboxysome's enzymatic core and uses narrow pores to control the passage of small molecules. In this review, we summarize recent advances in understanding the organization and functioning of these intriguing, and ecologically very important molecular machines.

Publication types

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

MeSH terms

  • Bacterial Proteins / metabolism
  • Bicarbonates / metabolism
  • Carbon / metabolism*
  • Carbon Cycle / physiology
  • Carbon Dioxide / metabolism
  • Carbonic Anhydrases / metabolism*
  • Cyanobacteria / enzymology*
  • Cyanobacteria / metabolism
  • Cyanobacteria / ultrastructure
  • Models, Molecular
  • Organelles / enzymology*
  • Organelles / metabolism
  • Organelles / ultrastructure
  • Ribulose-Bisphosphate Carboxylase / metabolism*

Substances

  • Bacterial Proteins
  • Bicarbonates
  • Carbon Dioxide
  • Carbon
  • Ribulose-Bisphosphate Carboxylase
  • Carbonic Anhydrases