The carboxysome, a prokaryotic organelle: a mini-review

Abstract

Since first being isolated and named carboxysomes more than 17 years ago, these prokaryotic inclusions have been studied with great interest. Several summary statements can be made regarding the structure, composition, and function of carboxysomes. The carboxysome is composed of 7–15 peptides, of which 3–5 are shell glycoproteins. The only enzyme demonstrated to be associated with the carboxysomes is ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The carboxysome may be a dodecahedron or an icosahedron. The molecular weight of the carboxysomes from Thiobacillus neapolitanus is approximately 2.4 × 108. Rubisco may fill the carboxysome or line the inner surface of the shell. The carboxysome is active in CO2 fixation. The function of the carboxysome is related to the availability of CO2 to the cells. The molecular mechanisms of carboxysome function are not yet available. Key words: carboxysomes, review, ribulose-1,5-bisphosphate carboxylase/oxygenase, Rubisco, structure, composition.