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Team:Bielefeld-CeBiTec/Results/CO2-fixation/Carboxysome
From 2014.igem.org
CO2 fixation
Theory
The carboxysome is a protein-based microcompartement for the carbon fixation in cyanobacteria like Synechococus elangatus or Halothiobacillus neapolitanus. It is composed of thousands of subunits including hexameric and pentameric proteins that form a shell to encapsulate the enzymes Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and the carbonic anhydrase. The compartimentalization allows an incrasing substrate concentration within this microcompartement and therefore an improved catalytic efficiency of the encapsulated enzymes.
First of all carbonate (HCO3-) diffuse into the caboxysome and is than converted into carbon dioxide (CO2) enabling high substrate concentration for the Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), which catalyzse the fixation of carbon dioxide and ribulose 1,5-bisphosphate into 3-phosphogylcerate. In the presence of oxygen (O2) the RuBisCO produces phosphoglycolate, a waste product which must be recycled by the cell. As carbon dioxide and oxygen competivly bind as substrates of the RubisCO, the accumulation of carbon dioxide by the carbonic anhydrase and the prevention of oxygen diffusion by the barrier of the carboxysome shell enables an efficient carbon dioxide fixation
GFP-Fusion
Cloaning approach and purification
