Carboxysomes and Their Structural Organization In Prokaryotes

Carboxysomes are the archetypical examples of primitive proteinaceous organelles found in bacteria, collectively termed bacterial microcompartments (BMCs). Recent studies using current techniques for imaging and structural elucidation have resulted in a quantum leap of our mechanistic understanding of structure/function relationships in these bacterial inclusions. Bioinformatic analysis of the rapidly growing collection of sequenced bacterial genomes has revealed that BMCs of different types appear to be widely employed by microbes to organize their metabolism in much the same way that eukaryotes use sensu stricto organelles. This review focuses on some recently revealed properties of carboxysomes and points out pressing open questions. Some of these questions have remained unanswered since the discovery of carboxysomes; others have been raised by more recent discoveries