Wednesday, March 2, 2011
RuBisCo, or ribulose-1,5-bisphosphate carboxylase oxygenase has 16 chains - 8 large chains and 8 small chains. Each large chain is paired with a small chain, forming a heterodimer. The heterodimers further dimerize, forming four-chain complexes which are axial symmetrical. Four identical tetramers circle up to form the overall protein. Above, the protein is color coded by chain. The long chains are green or blue and the short chains are yellow or red. Each quadrant (blue or green) has two large chains. The small chains fit above (toward the viewer) or below (away from the viewer, on the back side) the large chains, and they are slightly offset, sitting in between the large chain subunits.