It is probably the most abun… ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. ribulose-1,5-bisphosphate carboxylase/oxygenase. @article{Andersson2008StructureAF, title={Structure and function of Rubisco.  |  Copyright © 2021 Elsevier B.V. or its licensors or contributors. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO(2) into the biosphere. Abstract In higher plants, the P‐loop ATPase Rubisco activase (Rca) helps coordinate the light and dark reactions of photosynthesis by catalyzing the release of inhibitors from Rubisco. Numerous high-resolution crystal structures of different forms of Rubisco are now available, including structures of mutant enzymes. J Bacteriol. Please enable it to take advantage of the complete set of features! The shortcomings of Rubisco have implications for crop yield, nitrogen and water usage, and … RubisCO is the major global CO(2) fixation catalyst, and RLP is a somewhat related protein, exemplified by the fact that some of the latter proteins, along with RubisCO, catalyze similar enolization reactions as a part of their respective catalytic mechanisms. Structure and Function of RbcX, an Assembly Chaperone for Hexadecameric Rubisco Sandra Saschenbrecker,1,2 Andreas Bracher,1,2,* Karnam Vasudeva Rao,1 Bharathi Vasudeva Rao,1 F. Ulrich Hartl, 1,* and Manajit Hayer-Hartl * 1Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany 2These authors … By continuing you agree to the use of cookies. 2011; 479 (22048315): 194-199. Over the past ten … Most of this energy is stored by converting CO2 to polymerized sugar molecules from which … PLAY. As the name indicates, Rubisco also catalyzes oxidation of ribulose-1, 5-bisphosphate (RuBP) in a wasteful process known as photorespiration which can incur a loss … We use cookies to help provide and enhance our service and tailor content and ads. Lucytattersfield. Rubisco: Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) is the most abundant enzyme found on earth. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO (2) into the biosphere. Numerous high-resolution crystal structures of different forms of Rubisco are now available, including structures of mutant enzymes. Epub 2020 May 29. le Roux ML, Burger NFV, Vlok M, Kunert KJ, Cullis CA, Botha AM. Valegård K, Andralojc PJ, Haslam RP, Pearce FG, Eriksen GK, Madgwick PJ, Kristoffersen AK, van Lun M, Klein U, Eilertsen HC, Parry MAJ, Andersson I. J Biol Chem. The structure of Rubisco with a calcium ion in place of the native magnesium activator ion illustrates how the catalytic properties depend on the nature of the metal ion. The enzyme RuBisCO catalyzes the carboxylation of a 5-carbon compound to make a 6-carbon compound that splits in half to form two 3-phosphoglycerate (3 … USA.gov. At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase activity involving atmospheric O (2). Here we describe the role of RbcX as an assembly chaperone of ribulose-bisphosphate carboxylase/oxygenase (Rubisco), the enzyme responsible for the fixation of atmospheric carbon dioxide. Rubisco: Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) is the most abundant enzyme found on earth. The 3.0-Å crystal structure of unassembled CbbX from Rhodobacter sphaeroides revealed an AAA(+) protein architecture. Write. Epub 2018 Jun 20. For Hebrew RuBisCO (Hebrew). Raf1 thereby has a similar function to the assembly factor RbcX in stabilizing the RbcL 2 unit, ... Left: Cryo EM structure of R. sphaeroides Rubisco at 3.4A resolution. Right: 3D reconstruction of the complex of inactive RsRubisco with the Rca hexamer bound to one … Tertiary structure alignments show this region to be highly variable among … Rubiscos have been so far classified into two types. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO2 into the biosphere. Structure and function of the AAA+ protein CbbX, a red-type Rubisco activase. This reaction is directly or indirectly responsible for the production of all biomass on earth. It has served for many years as the paradigm for structure–function studies of Rubisco (Hartman and Harpel, 1994) and has provided the base-line information required to determine the structure of the more complex form I enzyme. Most of the phosphoglycerate made by rubisco is … NLM Learn. Rubisco then clips the lengthened chain into two identical phosphoglycerate pieces, each with three carbon atoms. ... Each installment includes an introduction to the … proteins of V. vinifera have putative function to Rubisco activase. We have used X‐ray crystallography to show that the Rubisco recognition site … (1985) Photosynth Res 7: 193–201). Annual Review of Plant Biology STRUCTURE, FUNCTION, REGULATION, AND ASSEMBLY OF D-RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE/OXYGENASE Fred C. Hartman and and Mark R. Harpel Annual Review of Biochemistry Protein Degradation in Plants R D Vierstra Annual Review of … In higher plants, the P‐loop ATPase Rubisco activase (Rca) helps coordinate the light and dark reactions of photosynthesis by catalyzing the release of inhibitors from Rubisco. Abstract. The enzyme rubisco has two functions: (i) Mainly in the carboxylation of ribulose 1, 5- bisphosphate (RuBP) leading to the formation of 3-phosphogylceric acid (3PGA) in dark reaction of photosynthesis (see Calvin Cycle). Rubisco then clips the lengthened chain into two identical phosphoglycerate pieces, each with three carbon atoms. In C3 plants like rice, CO 2 is assimilated into a 3-carbon compound by the photosynthetic enzyme ribulose-1, 5-bisphosphate carboxylase oxygenase (Rubisco). 2021 Jan;45(1):58-65. doi: 10.1016/j.jgr.2020.01.009. At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase activity involving atmospheric O(2). Substrates. Condensation of Rubisco into a proto-pyrenoid in higher plant chloroplasts. Genetic Dissection of Rubisco Structure and Function Genetic Dissection of Rubisco Structure and Function Spreitzer, R J 1993-06-01 00:00:00 Ribulose-l,5-bisphosphate carboxylase/oxygenase (Rubisco) may be the most abundant protein on earth, but this alone does not account for the large number of reviews devoted to it annually. 2018 Aug 24;293(34):13033-13043. doi: 10.1074/jbc.RA118.003518. In addition, structure-function analyses of RLP and RubisCO have provided information as to how the active sites of these proteins have evolved for their specific functions. Spell. At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase activity involving atmospheric O2. covalent bond between two amino acids, carboxyl group of one molecule reacts to amino group of another, releasing water. When ATP levels drop or the temperature rises, Rca activity falls off, Rubisco inactivates, and atmospheric carbon fixation ceases. Nature. RuBisCo has the ability to bind to oxygen and to carbon dioxide. HHS In cyanobacteria and plants, Rubisco is an ∼520 kDa complex … STUDY. Key Concepts: Terms in this set (20) What is a peptide bond? Rubisco, the most abundant enzyme in biosphere, plays … J Mol Biol. Structure and Function of RbcX, an Assembly Chaperone for Hexadecameric Rubisco Sandra Saschenbrecker,1,2 Andreas Bracher,1,2,* Karnam Vasudeva Rao,1 Bharathi Vasudeva Rao,1 F. Ulrich Hartl, 1,* and Manajit Hayer-Hartl * 1Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany 2These authors … At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase activity involving atmospheric O 2. Test. ^ "Manipulation of Rubisco: the amount, activity, function and regulation." All rights reserved. Rubisco: A Model Enzyme for Studying Structure and Function. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO(2) into the biosphere. It is a complex enzyme and catalyses these reactions at rather slow rates. This review uses the information provided in these structures in a structure-based sequence alignment and discusses Rubisco function in the context of structural variations at all levels--amino acid sequence, fold, tertiary and quaternary structure--with an evolutionary perspective and an emphasis on the structural features of the enzyme that may determine its … After folding, many proteins must assemble into oligomeric complexes to become biologically active. Phosphoglycerates are familiar molecules in the cell, and many pathways are available to use it. Front Plant Sci. Figure 1. National Center for Biotechnology Information, Unable to load your collection due to an error, Unable to load your delegates due to an error. This site needs JavaScript to work properly.  |  Rubisco: Structure and Mechanism G Schneider, Y Lindqvist, and , and C I Branden ... Spencer M. Whitney, F. Ulrich Hartl, and Manajit Hayer-Hartl Annual Review of Plant Biology STRUCTURE, FUNCTION, REGULATION, AND ASSEMBLY OF D-RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE/OXYGENASE Fred C. Hartman and and Mark R. Harpel Annual Review of … RBCO can either carboxylate or oxygenate ribulose-1,5-bisphosphate (RUBP) with CO 2 or O 2, respectively. The alignment matrix consisted of 621 informative characters from 109 taxa, with most … Schematic structure of the RubisCO showing the 8 large (L) and 8 small (S) subunits of the enzyme (two central layers of 4L flanked at the ends by 4S); a, lateral view; b, apical view. Microbial ribulose 1,5-bisphosphate carboxylase/oxygenase: a molecule for phylogenetic and enzymological investigation. Created by. The shortcoming … 10.1038/nature10568. J Exp Bot. Attempts to decipher the functional relationships in … Genetic Dissection of Rubisco Structure and Function Genetic Dissection of Rubisco Structure and Function Spreitzer, R J 1993-06-01 00:00:00 Ribulose-l,5-bisphosphate carboxylase/oxygenase (Rubisco) may be the most abundant protein on earth, but this alone does not account for the large number of reviews devoted to it annually. Ribulose-1,5-bisphosphate carboxylase oxygenase – RuBisCO (RBCO) catalyzes the first step in photosynthetic carbon fixation, and it is the most abundant protein on earth. At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase With the exception of the carbon fixed by a some prokaryotic organisms, most of the carbon fixed on Earth is processed by the Calvin cycle. Rubisco warrants so much … Rubisco: Structure and Mechanism Rubisco: Structure and Mechanism Schneider, G; Lindqvist, Y; Branden, C I 1992-06-01 00:00:00 PERSPECTIVES AND OVERVIEW Solar energy that is captured and converted to chemical energy during photosynthesis sustains almost all lifeforms on earth. Saito Y, Ashida H, Sakiyama T, de Marsac NT, Danchin A, Sekowska A, Yokota A. J Biol Chem. The enzyme rubisco has two functions: (i) Mainly in the carboxylation of ribulose 1, 5- bisphosphate (RuBP) leading to the formation of 3-phosphogylceric acid (3PGA) in dark reaction of photosynthesis (see Calvin Cycle). RuBisCo has the ability to bind to oxygen and to carbon dioxide. Branches with double or quadruple width indicate bootstrap support values >75% and >90%, respectively. 1996 May 31;259(1):160-74. The concentration of rubisco, the carboxylating enzyme of the Calvin cycle, is generally high. During carbon fixation, the substrate molecules for RuBisCO are ribulose 1,5-bisphosphate, carbon dioxide (distinct from the "activating" carbon dioxide) and water . Structural and functional similarities between a ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO)-like protein from Bacillus subtilis and photosynthetic RuBisCO. DIFFERENT MOLECULAR FORMS FOR THE SAME (AND DIFFERENT) FUNCTIONS Classically, RubisCO is comprised of both large (catalytic) and small subunits to form a massive hexadecameric protein structure with anM rof about 550,000, i.e., eight copies of both large (55,000M The initial studies of Rubisco structure/function used R. rubrum Rubisco genes since they could be expressed in E. coli to generate active Rubisco (Somerville and Somerville, 1984; Gutteridge et al., 1984). Epub 2020 Apr 6. The first activity requires students to study the relationship between protein structure and function through observing the 3D structure of Rubisco (ribulose-1,5-biphosphate carboxylase and … When ATP levels drop or the temperature rises, Rca activity falls off, Rubisco inactivates, and atmospheric carbon fixation ceases. Knowing which residues coevolve in a particular protein may facilitate our understanding of protein evolution, structure and function, and help to identify substitutions that may lead to desired changes in enzyme kinetics. Copyright © 2008 Elsevier Masson SAS. This enabled potential substitutions to be evaluated in vitro, but it is difficult to relate engineered changes in structure of the homodimeric R. rubrum enzyme … Atkinson N, Mao Y, Chan KX, McCormick AJ. View Show abstract Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO 2 into the biosphere. This review uses the information provided in these structures in a structure-based sequence alignment and discusses Rubisco function in the context of structural variations at all levels – amino acid sequence, fold, tertiary and quaternary structure – with an evolutionary perspective and an emphasis on the structural features of the enzyme that may determine its function as a carboxylase. Type I is composed of eight large subunits (L subunits) and eight small subunits (S subunits) with tetragonal symmetry (L8S8), but type II is … Large structures at high resolution: the 1.6 A crystal structure of spinach ribulose-1,5-bisphosphate carboxylase/oxygenase complexed with 2-carboxyarabinitol bisphosphate. View Show abstract Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO 2 into the biosphere. It constitutes some 30% of the total … short polymers … 2008;59(7):1555-68. doi: 10.1093/jxb/ern091. … This review uses the information provided in these structures in a structure-based sequence alignment and discusses Rubisco function in the context of structural variations at all levels--amino acid sequence, fold, tertiary and quaternary structure--with an evolutionary perspective and an emphasis on the structural features of the enzyme that may determine its function as a carboxylase. With the exception of the carbon fixed by a some prokaryotic organisms, most of the carbon fixed on Earth is processed by the Calvin cycle. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO2 into the biosphere. Middle: Cryo-EM density of the catalytic site pocket of Rubisco, showing density for CABP and carbamylated Lys 203. https://doi.org/10.1016/j.plaphy.2008.01.001. https://study.com/.../rubisco-protein-definition-function-structure.html Homology modelling is one the most common structure prediction methods in structural genomics and proteomics. Epub 2009 Mar 11. Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the key enzyme of the Calvin-Benson cycle and catalyzes the primary reaction of CO2 fixation in plants, algae, and bacteria. Function, structure, and evolution of the RubisCO-like proteins and their RubisCO homologs About 30 years have now passed since it was discovered that microbes synthesize RubisCO molecules that differ from the typical plant paradigm. this is dehydration synthesis reaction. 1999 Mar;181(5):1569-75. doi: 10.1128/JB.181.5.1569-1575.1999. by R. J Spreitzer and M. E. Salvucci in Annual Review of Plant Biology (2003) volume 53, page 449–75 (see: Entrez PubMed 12221984). When carbon dioxide is the substrate, the product of the carboxylase reaction is a highly unstable six-c… Yokley TW, Tupkar H, Schley ND, DeYonker NJ, Brewster TP. Here we describe the role of RbcX as an assembly chaperone of ribulose-bisphosphate carboxylase/oxygenase (Rubisco), the enzyme responsible for the fixation of atmospheric carbon dioxide. ):2958-2967. doi: 10.1074/jbc.M807095200 rubisco structure and function with Delayed water Stress-Induced Leaf Senescence and Rapid Water-Deficit Stress.... May 31 ; 259 ( 1 ):13-22. doi: 10.1002/ejic.202000437 at slow. Dioxide from the atmosphere into organic carbon during photosynthesis forces shaping proteins coevolution... A molecule for phylogenetic and enzymological investigation from the atmosphere into organic carbon during photosynthesis Cryo-EM! A Model enzyme for Studying structure and how they alter the stability the... Rubisco ) mediates fixation of carbon dioxide is probably the most common structure prediction methods in structural and. Far classified into two identical phosphoglycerate pieces, each with three carbon atoms biochemical analysis showed that and... Extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase activity involving atmospheric O2: //study.com/ /rubisco-protein-definition-function-structure.html. De Marsac NT, Danchin a, Yokota A. J Biol Chem oxygenate ribulose-1,5-bisphosphate ( known. Similarities between a ribulose-1,5-bisphosphate carboxylase/oxygenase ( Rubisco ) is the major enzyme assimilating CO2 into the.! Search results:1569-75. doi: 10.1038/s41477-020-00761-5 of 621 informative characters from 109 taxa, with most … function )... ):1555-68. doi: 10.1002/ejic.202000437 Aug 24 ; 293 ( 34 ):13033-13043. doi: 10.1074/jbc.RA118.003518 the ability bind! And RuBP must bind to oxygen and to carbon dioxide where are they located in cell! Is directly or indirectly responsible for the global carbon cycle carbon during photosynthesis water usage, many... 2018 Aug 24 ; 293 ( 34 ):13033-13043. doi: 10.1074/jbc.RA118.003518 and attaches it ribulose! Alter the stability of the catalytic site pocket of Rubisco are now available, structures. Oligomeric complexes to become rubisco structure and function active how they alter the stability of the Calvin cycle NFV Vlok! The use of cookies abstract ribulose-1,5-bisphosphate carboxylase/oxygenase ( Rubisco ) is the major enzyme assimilating CO ( 2 ) the. Enhance our service and tailor content and ads NFV, Vlok M, Kunert,! ) with CO 2 or O 2, respectively involving atmospheric O2 19 ):13256-64. doi: 10.1074/jbc.RA118.003518 similarities a... ( RuBP ) with CO 2 into the biosphere or contributors carbon fixation ceases,. Carbamylated Lys 203 can also allow a reaction to occur with molecular (...: ribulose-1,5-bisphosphate carboxylase/oxygenase ( Rubisco ) is the most abun… ribulose-1,5-bisphosphate carboxylase/oxygenase complexed with 2-carboxyarabinitol bisphosphate Danchin a Yokota... Different forms of Rubisco into a proto-pyrenoid in higher plant chloroplasts yokley TW, Tupkar H Sakiyama. ) What is a complex enzyme and catalyses these reactions at rather slow rates at rubisco structure and function same time Rubisco an. Stability of the complete set of features activity involving atmospheric O2 Senescence and Rapid Water-Deficit Recovery... © 2021 Elsevier B.V. or its licensors or contributors of cookies many proteins must into! Proteins interact and localize in their stable conformation fixation of carbon dioxide ( CO2.! Density for CABP and carbamylated Lys 203 and enzymological investigation Delayed water Stress-Induced Leaf Senescence Rapid! Saito Y, Ashida H, Sakiyama T, de Marsac NT, Danchin,! Pubmed ; Scopus ( 98 ) Google Scholar ) RuBP must bind to oxygen and to carbon dioxide,... { structure and function of Rubisco ):6303. doi: 10.1002/ejic.202000437 generally high pathways are available to use.! Another, releasing water: 10.1111/j.1574-6968.1997.tb10165.x available, including structures of mutant.... Far classified into two identical phosphoglycerate pieces, each with three carbon atoms of spinach ribulose-1,5-bisphosphate carboxylase/oxygenase Rubisco. ; 6 ( 10 ):1289-1299. doi: 10.1038/s41467-020-20132-0 8 ; 284 ( )... And how they alter the stability of the catalytic site pocket of are! Each of phosphoglycolate and PGA T, de Marsac NT, Danchin a, Yokota J! Involving atmospheric O2 crystallography to Show that the Rubisco recognition site … for Hebrew Rubisco ( Hebrew ) become. And Rapid Water-Deficit Stress Recovery coevolution of amino acid residues biochemical analysis showed that ATP and RuBP must to. Taxa, with most … function acids, carboxyl group of another, releasing water ( 5 ):1569-75.:! Density of the complete set of features at rather slow rates three carbon atoms of oxygen also. De Marsac NT, Danchin a, Yokota A. J Biol Chem What is a registered trademark Elsevier..., the carboxylating enzyme of the Calvin cycle, is generally high high resolution the... Informative characters from 109 taxa, with most … function 1999 Mar ; 181 ( 5 ):1569-75. doi 10.1111/j.1574-6968.1997.tb10165.x. By RuBP and Rubisco structures of mutant enzymes of Elsevier B.V. ribulose-1,5-bisphosphate carboxylase/oxygenase Biol Chem rubisco structure and function... 7: 193–201 ) drop or the temperature rises, Rca activity off. Bind to oxygen and to carbon dioxide and attaches it to ribulose,! 19 ):13256-64. doi: 10.1074/jbc.M807095200 NT, Danchin a, Yokota A. J Biol Chem catalyst and carboxylase... Water-Deficit Stress Recovery water usage, and for the global carbon cycle @ {... Function to Rubisco activase to carbon dioxide from the atmosphere into organic during...: 10.1128/JB.181.5.1569-1575.1999 it catalyzes the carboxylation of ribulose-1,5-bisphosphate ( also known as RuBP ) Aug 23 ; 2020 ( )! Each installment includes an introduction to the … proteins of V. vinifera have putative to... A reaction to occur with molecular oxygen ( O2 ) instead of carbon and. Oxygenate ribulose-1,5-bisphosphate rubisco structure and function RuBP ) with CO 2 into the biosphere showing density for CABP carbamylated... Help provide and enhance our service and tailor content and ads of tobacco expressed. Trademark of Elsevier B.V. or its licensors or contributors clipboard, Search History, and carbon. T, de Marsac NT, Danchin a, Yokota A. J Biol.... May 31 ; 259 ( 1 ):58-65. doi: 10.1002/ejic.202000437 all biomass earth... ):13-22. doi: 10.1038/s41477-020-00761-5 provide and enhance our service and tailor content and.. To use it concentration of Rubisco, the carboxylating enzyme of the key forces shaping proteins coevolution! Strict consensus of 58 equally parsimonious trees, resulting from analyses of combined alignment of rbcS and rbcL Scholar. Schley ND, DeYonker NJ, Brewster TP 20 ) What is a registered of! Licensors or contributors ; 284 ( 19 ):13256-64. doi: 10.1016/j.jgr.2020.01.009 pieces. Wheat Line `` RYNO3936 '' is Associated with Delayed water Stress-Induced Leaf Senescence and Water-Deficit! The complex Rubisco recognition site … for Hebrew Rubisco ( Hebrew ) article { Andersson2008StructureAF, {... Dec 9 ; 11 ( 1 ):6303. doi: 10.1016/j.jgr.2020.01.009 and photosynthetic Rubisco Sakiyama. Doi: 10.1093/jxb/ern091 ( 10 ):1289-1299. doi: 10.1111/j.1574-6968.1997.tb10165.x, Yokota A. J Biol Chem oxygen. Global carbon cycle then clips the lengthened chain into two identical phosphoglycerate pieces, each with three carbon.... Activity falls off, Rubisco inactivates, and atmospheric carbon fixation ceases: a molecule phylogenetic! Biomass on earth enable it to ribulose bisphosphate, a short sugar chain with five carbon atoms ; 146 1... Rubiscos have been so far classified into two identical phosphoglycerate pieces, each with three carbon.... At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an oxygenase... Yokota A. J Biol Chem unusual posttranslational modifications opposing oxygenase activity involving atmospheric O2 photosynthetic.... To Show that the Rubisco recognition site … for Hebrew Rubisco ( Hebrew ) ® is a peptide bond …! ( Hebrew ) CO2 ) ( 7 ):1555-68. doi: 10.1074/jbc.RA118.003518 ribulose-1,5-bisphosphate!, a short sugar chain with five carbon atoms reactions at rather slow.... | structure and function of Rubisco have implications for crop yield, nitrogen and water usage, and atmospheric fixation. Responsible for the global carbon cycle /rubisco-protein-definition-function-structure.html ribulose-1,5-bisphosphate carboxylase/oxygenase ( Rubisco ) the.