Carboxysomal Carbonic Anhydrases: Structure and Role in Microbial CO₂ Fixation

Authors

Gordon C. Cannon, University of Southern MississippiFollow
Sabine Heinhorst, University of Southern MississippiFollow
Cheryl A. Kerfeld, University of California

Document Type

Article

Publication Date

2-1-2010

Department

Chemistry and Biochemistry

School

Mathematics and Natural Sciences

Abstract

Cyanobacteria and some chemoautotrophic bacteria are able to grow in environments with limiting CO₂ concentrations by employing a CO₂-concentrating mechanism (CCM) that allows them to accumulate inorganic carbon in their cytoplasm to concentrations several orders of magnitude higher than that on the outside. The final step of this process takes place in polyhedral protein microcompartments known as carboxysomes, which contain the majority of the CO₂-fixing enzyme, RubisCO. The efficiency of CO₂ fixation by the sequestered RubisCO is enhanced by co-localization with a specialized carbonic anhydrase that catalyzes dehydration of the cytoplasmic bicarbonate and ensures saturation of RubisCO with its substrate, CO₂. There are two genetically distinct carboxysome types that differ in their protein composition and in the carbonic anhydrase(s) they employ. Here we review the existing information concerning the genomics, structure and enzymology of these uniquely adapted carbonic anhydrases, which are of fundamental importance in the global carbon cycle.

Comments

© 2010. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

Publication Title

Biochimica et Biophysica Acta-Proteins and Proteomics

Volume

1804

Issue

2

First Page

382

Last Page

392

Recommended Citation

Cannon, G. C., Heinhorst, S., Kerfeld, C. A. (2010). Carboxysomal Carbonic Anhydrases: Structure and Role in Microbial CO₂ Fixation. Biochimica et Biophysica Acta-Proteins and Proteomics, 1804(2), 382-392.
Available at: https://aquila.usm.edu/fac_pubs/8895