InterPro domain: IPR020888

Ribulose bisphosphate carboxylase (RuBisCO) [ 1 , 2 ] catalyses the initial step in Calvin's reductive pentose phosphate cycle in plants as well as purple and green bacteria. It catalyzes the primary CO2 fixation step. RuBisCO consists of a large catalytic unit and a small subunit of undetermined function. In plants, the large subunit is coded by the chloroplastic genome while the small subunit is encoded in the nuclear genome. Rubisco is activated by carbamylation of an active site lysine, stabilized by a divalent cation, which then catalyzes the proton abstraction from the substrate ribulose 1,5 bisphosphate (RuBP) and leads to the formation of two molecules of 3-phosphoglycerate [ 3 , 4 ].

Members of the Rubisco family can be divided into 4 subgroups, form I-IV , which differ in their taxonomic distribution and subunit composition [ 5 , 6 ]. Form I is the most abundant class, present in plants, algae, and bacteria, and forms large complexes composed of 8 large and 8 small subunits.

1. Ribulose-1,5-bisphosphate carboxylase-oxygenase. Annu. Rev. Biochem. 52, 507-35
2. Rubisco: structure, regulatory interactions, and possibilities for a better enzyme. J. Biol. Chem. 53, 449-75
3. Examination of the intersubunit interaction between glutamate-48 and lysine-168 of ribulose-bisphosphate carboxylase/oxygenase by site-directed mutagenesis. J. Mol. Biol. 265, 6501-5
4. The structure of the complex between rubisco and its natural substrate ribulose 1,5-bisphosphate. Microbiol. Mol. Biol. Rev. 265, 432-44
5. Distinct form I, II, III, and IV Rubisco proteins from the three kingdoms of life provide clues about Rubisco evolution and structure/function relationships. null 59, 1515-24
6. Function, structure, and evolution of the RubisCO-like proteins and their RubisCO homologs. J. Exp. Bot. 71, 576-99