Structure and encapsulation of carbonic anhydrase within the α-carboxysome.

ABSTRACT: Carboxysomes in cyanobacteria and certain proteobacteria enable efficient CO₂ fixation by encapsulating ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and carbonic anhydrase (CA) within a semipermeable shell. Sequestered CA catalyze the rapid interconversion of CO₂ and HCO₃^-, supplying elevated levels of CO₂ to boost Rubisco carboxylation. Despite its essential role, the structure and encapsulation of CA within carboxysomes remain poorly understood. Here, we determined the molecular structure of α-carboxysomal CA from the model chemoautotrophic bacterium Halothiobacillus neapolitanus (HnCsoSCA). HnCsoSCA adopts a trimer-of-dimers oligomeric structure without the incorporation of a zinc ion at its symmetr

SUBMITTER: Ng PC 

PROVIDER: S-EPMC12646314 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature