Abstract
Under the poor availability of inorganic carbon (such as CO2, HCO3- :Ci) for photosynthesis, Chlamydomonas or cyanobacteria induce the active uptake systems for Ci that allow accumulation of Ci within the cell (Carbon-Concentrating Mechanism: CCM). In Chlamydomonas, the regulatory factor CCM1 is indispensable to induce the CCM. CCM1 has five Cys residues conserved in the zinc-finger domain in its N-terminal region. In order to analyze the zinc atom occupancy, we generated E. coli expressed GST fusion N-terminal region of the CCM1. Zinc ion was detected in this fusion protein by the atomic absorption analysis. In order to detect the CCM1 protein, western blot analysis against soluble Chlamydomonas protein fraction was performed. A 95-kDa band was detected by anti-CCM1 antibody. Considering with the fact that the deduced molecular weight of the CCM1 was 70.073 kDa, some modifications of the CCM1 were suggested. The CCM1 was expressed constitutively independent of CO2 availability.
