RuBisCO
Ribulose-1,5-bisphosphate carboxylase oxygenase, better known as RuBisCO,[note 1] is an enzyme that catalyzes the first major step of carbon fixation in the Calvin cycle. Carbon fixation is how the atoms of atmospheric carbon dioxide are made available to organisms in the form of energy-rich molecules such as glucose. RuBisCO splits 6-C molecules into two equal parts.
RuBisCO is very important in biology and ecology because it catalyzes the primary chemical reaction by which inorganic carbon permanently enters the biosphere.
RuBisCO is also the most abundant protein in leaves and the most abundant protein on Earth.[3][4][5] It accounts for 50% of soluble leaf protein (20-30% of total leaf nitrogen) and 30% of soluble leaf protein in plants (5-9% of total leaf nitrogen).[5]
Given its important role in the biosphere, there are currently efforts to genetically engineer crop plants to contain more efficient RuBisCO.[6]
Notes and references
- Notes
- References
RuBisCO Media
Location of the rbcL gene in the chloroplast genome of Arabidopsis thaliana (positions ca. 55-56.4 kb). rbcL is one of the 21 protein-coding genes involved in photosynthesis (green boxes).
Two main reactions of RuBisCo: Template:CO2 fixation and oxygenation.
A 3D image of the active site of spinach RuBisCO complexed with the inhibitor 2-carboxyarabinitol-1,5-bisphosphate, Template:CO2, and Mg2+. (PDB: 1IR1; Ligand View [CAP]501:A)
Overview of the Calvin cycle and carbon fixation.
Figure 3. In this figure, each protein chain in the (LS)2 complex is given its own color for easy identification.
- ↑ Wildman SG (2002). "Along the trail from fraction I protein to Rubisco (ribulose bisphosphate carboxylase-oxygenase)". Photosyn. Res. 73 (1–3): 243–50. doi:10.1023/A:1020467601966. PMID 16245127. S2CID 7622999.
- ↑ Portis AR, Parry MA (October 2007). "Discoveries in Rubisco (Ribulose 1,5-bisphosphate carboxylase/oxygenase): a historical perspective". Photosyn. Res. 94 (1): 121–43. doi:10.1007/s11120-007-9225-6. PMID 17665149. S2CID 39767233.
- ↑ Cooper, Geoffrey M. (2000). "10.The Chloroplast Genome". The Cell: a molecular approach (2nd ed.). Washington, D.C: ASM Press. ISBN 0-87893-106-6.
One of the subunits of ribulose bisphosphate carboxylase (rubisco) is encoded by chloroplast DNA. Rubisco is the critical enzyme which catalyzes the addition of CO2 to ribulose-1,5-bisphosphate during the Calvin cycle (see Figure 2.39). Not only is it the major protein component of the chloroplast stroma but it is also thought to be the single most abundant protein on Earth, so it is noteworthy that one of its subunits is encoded by the chloroplast genome.
- ↑ Dhingra A, Portis AR, Daniell H (April 2004). "Enhanced translation of a chloroplast-expressed RbcS gene restores small subunit levels and photosynthesis in nuclear RbcS antisense plants". Proc. Natl. Acad. Sci. U.S.A. 101 (16): 6315–20. Bibcode:2004PNAS..101.6315D. doi:10.1073/pnas.0400981101. PMC 395966. PMID 15067115.
(Rubisco) is the most prevalent enzyme on this planet, accounting for 30–50% of total soluble protein in the chloroplast.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ↑ 5.0 5.1 Feller U, Anders I, Mae T (2008). "Rubiscolytics: fate of Rubisco after its enzymatic function in a cell is terminated". J. Exp. Bot. 59 (7): 1615–24. doi:10.1093/jxb/erm242. PMID 17975207.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ↑ Ellis, R. John 2010. Biochemistry: tackling unintelligent design. Nature 463, 164-165 doi:10.1038/463164a [1]