[Progress in structure and CO2-concentrating mechanism of carboxysomes]

Carboxysomes are extremely efficient microcompartments committed to CO2 fixation due to tailored CO2-concentrating mechanism (CCM). In cyanobacteria and some chemoautotrophs, carboxysomes as organelle-like microbodies encapsulate ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and carbonic anhydrase (CA). Together with active inorganic carbon uptake transporters, carboxysomes accumulate HCO3(-) in the cytoplasm, leading to high efficiency of carbon fixation. Based on the elucidation of structures and functionalities, heterologous production of carboxysomes has been achieved so far. In fact, the genes encoding either vacant carboxysome shell or only interior components have been characterized. This review summarizes the discovery along with types, showcases molecular structures and roles of carboxysomes in CCM, and presents their broad applications in metabolic engineering.