Abstract
CO2 plays redundant and crucial roles in some cellular physiology in many living organisms beyond kingdom. General method for measurements of inorganic carbon are valid for determination of total concentrations but unable to determine local concentrations in situ. In the present study, protein based nano sensor, which can detect inorganic carbon concentration in situ based upon FRET. For the base protein, carbonic anhydrase, which can bind to both HCO3- and CO2, and CmpA (a cyanobacterial periplasmic protein), which has a specific affinity for HCO3-. The CmpA gene was cloned from the genome of Synechococcus sp. PCC7942, truncated to 12 different lengths, and were ligated with the CFP gene and the YFP gene. These constructs were expressed in E. coli. FRET was measured using either intact cells or lysate of E. coli. As a result, we found some E coli clones in which efficient FRET was observed between CFP and YFP.
