The glycine cleavage system (GCS) is essential for all eukaryotes. It consists of four proteins, namely P-, L-, T- and H-protein, and converts glycine to serine. Early research from plants showed complex formation of these proteins under high concentrations in vitro but not in vivo with a ratio of 2P2:1L2:9T:27H.
Using the very similar proteins of the GCS from the model cyanobacteria Synechocystis sp. PCC 6803 we analysed if complex formation was possible for organisms other than plants.
The analysis showed complex formation of the Synechocystis proteins. Therefore, this GCS can be used as a model for further structure and function analysis, because in contrast to the plant proteins all cyanobacterial proteins can be expressed in a heterologous system.
Additionally, with mass spectrometry the known ration could be refined. For pea a ratio of 4P2:1L2:8T:28H and for the model plant Arabidopsis thaliana a ratio of 4P2:1L2:8T:20H was analysed.