Identification and functional role of the carbonic anhydrase Cah3 in thylakoid membranes of pyrenoid of Chlamydomonas reinhardtii

► The Cah3 of Chlamydomonas is located in the lumen of thylakoid membranes of pyrenoid. ► In cia3 mutant, Cah3 is evenly distributed throughout the pyrenoid matrix. ► CO2 for Rubisco might be generated by Cah3 from HCO3− in the thylakoid lumen. ► Cah3 utilized the excess of H+ generated during fatty avid desaturation. ► Thus, Cah3 participates in the restructuring of the photosynthetic membranes.