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The University of Southern Mississippi

Cyanobacteria

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Full-Text Articles in Chemistry

Carboxysomal Carbonic Anhydrases: Structure And Role In Microbial Co2 Fixation, Gordon C. Cannon, Sabine Heinhorst, Cheryl A. Kerfeld Feb 2010

Carboxysomal Carbonic Anhydrases: Structure And Role In Microbial Co2 Fixation, Gordon C. Cannon, Sabine Heinhorst, Cheryl A. Kerfeld

Faculty Publications

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 …


Halothiobacillus Neapolitanus Carboxysomes Sequester Heterologous And Chimeric Rubisco Species, Balaraj B. Menon, Zhicheng Dou, Sabine Heinhorst, Jessup M. Shively, Gordon C. Cannon Oct 2008

Halothiobacillus Neapolitanus Carboxysomes Sequester Heterologous And Chimeric Rubisco Species, Balaraj B. Menon, Zhicheng Dou, Sabine Heinhorst, Jessup M. Shively, Gordon C. Cannon

Faculty Publications

Background: The carboxysome is a bacterial microcompartment that consists of a polyhedral protein shell filled with ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), the enzyme that catalyzes the first step of CO(2) fixation via the Calvin-Benson-Bassham cycle. Methodology/Principal Findings: To analyze the role of RubisCO in carboxysome biogenesis in vivo we have created a series of Halothiobacillus neapolitanus RubisCO mutants. We identified the large subunit of the enzyme as an important determinant for its sequestration into alpha-carboxysomes and found that the carboxysomes of H. neapolitanus readily incorporate chimeric and heterologous RubisCO species. Intriguingly, a mutant lacking carboxysomal RubisCO assembles empty carboxysome shells of …