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Hermans C, Conn SJ, Chen J, Xiao Q, Verbruggen N. An update on magnesium homeostasis mechanisms in plants. Metallomics 2014; 5:1170-83. [PMID: 23420558 DOI: 10.1039/c3mt20223b] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Worldwide, nearly two-thirds of the population do not consume the recommended amount of magnesium (Mg) in their diet. Furthermore, low Mg status (hypomagnesaemia) is known to contribute to a number of human chronic disease conditions. Because the principal dietary Mg source is of plant origin, agronomic and genetic biofortification strategies are aimed at improving nutritional Mg content in food crops to overcome this mineral deficiency in humans. This update incorporates the contributions of annotated permeases involved in Mg uptake, storage and recycling with a schematic model of Mg movement at the organ and cellular levels in the model species Arabidopsis thaliana. Furthermore, approaches using mutagenesis or natural ionomic variation to identify loci involved in Mg homeostasis in roots, leaves and seeds will be summarised. A brief overview will be presented on how Arabidopsis research can help to develop strategies for biofortification of crops.
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Affiliation(s)
- Christian Hermans
- Laboratory of Plant Physiology and Molecular Genetics, Université Libre de Bruxelles, Campus Plaine CP 242, Bd du Triomphe, 1050 Brussels, Belgium.
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2
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Mueller-Cajar O, Stotz M, Bracher A. Maintaining photosynthetic CO2 fixation via protein remodelling: the Rubisco activases. PHOTOSYNTHESIS RESEARCH 2014; 119:191-201. [PMID: 23543331 DOI: 10.1007/s11120-013-9819-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/19/2013] [Indexed: 05/19/2023]
Abstract
The key photosynthetic, CO2-fixing enzyme Rubisco forms inactivated complexes with its substrate ribulose 1,5-bisphosphate (RuBP) and other sugar phosphate inhibitors. The independently evolved AAA+ proteins Rubisco activase and CbbX harness energy from ATP hydrolysis to remodel Rubisco complexes, facilitating release of these inhibitors. Here, we discuss recent structural and mechanistic advances towards the understanding of protein-mediated Rubisco activation. Both activating proteins appear to form ring-shaped hexameric arrangements typical for AAA+ ATPases in their functional form, but display very different regulatory and biochemical properties. Considering the thermolability of the plant enzyme, an improved understanding of the mechanism for Rubisco activation may help in developing heat-resistant plants adapted to the challenge of global warming.
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Affiliation(s)
- Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore,
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3
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Structure and function of the AAA+ protein CbbX, a red-type Rubisco activase. Nature 2011; 479:194-9. [PMID: 22048315 DOI: 10.1038/nature10568] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Accepted: 09/15/2011] [Indexed: 12/21/2022]
Abstract
Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the fixation of atmospheric CO(2) in photosynthesis, but tends to form inactive complexes with its substrate ribulose 1,5-bisphosphate (RuBP). In plants, Rubisco is reactivated by the AAA(+) (ATPases associated with various cellular activities) protein Rubisco activase (Rca), but no such protein is known for the Rubisco of red algae. Here we identify the protein CbbX as an activase of red-type Rubisco. The 3.0-Å crystal structure of unassembled CbbX from Rhodobacter sphaeroides revealed an AAA(+) protein architecture. Electron microscopy and biochemical analysis showed that ATP and RuBP must bind to convert CbbX into functionally active, hexameric rings. The CbbX ATPase is strongly stimulated by RuBP and Rubisco. Mutational analysis suggests that CbbX functions by transiently pulling the carboxy-terminal peptide of the Rubisco large subunit into the hexamer pore, resulting in the release of the inhibitory RuBP. Understanding Rubisco activation may facilitate efforts to improve CO(2) uptake and biomass production by photosynthetic organisms.
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Andrews TJ, Ballment B. Active-site carbamate formation and reaction-intermediate-analog binding by ribulosebisphosphate carboxylase/oxygenase in the absence of its small subunits. Proc Natl Acad Sci U S A 2010; 81:3660-4. [PMID: 16593473 PMCID: PMC345278 DOI: 10.1073/pnas.81.12.3660] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Even though depleted of more than 90% of its small subunits, ribulose 1,5-bisphosphate carboxylase/oxygenase from Synechococcus ACMM 323 still formed a stable complex with 2-carboxyarabinitol 1,5-bisphosphate from which exchange of the activator CO(2) molecule was prevented. The stoichiometry between nonexchangeable CO(2) and large subunits was unchanged regardless of the presence or absence of small subunits. The small-subunit-depleted enzyme was also "activated" by exposure to CO(2) and Mg(2+), although it was necessary for the small subunits to be bound before this "activation" could be expressed. Binding of small subunits occurred rapidly, its rate depending on subunit concentration. The initial rate of "activation" was not slowed in the absence of small subunits but its extent at equilibrium was reduced. These observations are not consistent with an obligate role for the small subunits in the activation process. Their necessity in catalysis must stem from a more subtle involvement in the catalytic mechanism itself.
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Affiliation(s)
- T J Andrews
- Australian Institute of Marine Science, PMB No. 3, IMC, Townsville, QLD 4810, Australia
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5
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Kane HJ, Wilkin JM, Portis AR. Potent inhibition of ribulose-bisphosphate carboxylase by an oxidized impurity in ribulose-1,5-bisphosphate. PLANT PHYSIOLOGY 1998; 117:1059-69. [PMID: 9662549 PMCID: PMC34922 DOI: 10.1104/pp.117.3.1059] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/1998] [Accepted: 04/02/1998] [Indexed: 05/18/2023]
Abstract
Oxidation of D-ribulose-1,5-bisphosphate (ribulose-P2) during synthesis and/or storage produces D-glycero-2,3-pentodiulose-1, 5-bisphosphate (pentodiulose-P2), a potent slow, tight-binding inhibitor of spinach (Spinacia oleracea L.) ribulose-P2 carboxylase/oxygenase (Rubisco). Differing degrees of contamination with pentodiulose-P2 caused the decline in Rubisco activity seen during Rubisco assay time courses to vary between different preparations of ribulose-P2. With some ribulose-P2 preparations, this compound can be the dominant cause of the decline, far exceeding the significance of the catalytic by-product, D-xylulose-1, 5-bisphosphate. Unlike xylulose-1,5-bisphosphate, pentodiulose-P2 did not appear to be a significant by-product of catalysis by wild-type Rubisco at saturating CO2 concentration. It was produced slowly during frozen storage of ribulose-P2, even at low pH, more rapidly in Rubisco assay buffers at room temperature, and particularly rapidly on deliberate oxidation of ribulose-P2 with Cu2+. Its formation was prevented by the exclusion of transition metals and O2. Pentodiulose-P2 was unstable and decayed to a variety of other less-inhibitory compounds, particularly in the presence of some buffers. However, it formed a tight, stable complex with carbamylated spinach Rubisco, which could be isolated by gel filtration, presumably because its structure mimics that of the enediol intermediate of Rubisco catalysis. Rubisco catalyzes the cleavage of pentodiulose-P2 by H2O2, producing P-glycolate.
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6
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Watson GM, Tabita FR. Microbial ribulose 1,5-bisphosphate carboxylase/oxygenase: a molecule for phylogenetic and enzymological investigation. FEMS Microbiol Lett 1997; 146:13-22. [PMID: 8997702 DOI: 10.1111/j.1574-6968.1997.tb10165.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) catalyzes the key reaction of the Calvin reductive pentose phosphate cycle and as such is responsible for life as we know it. This enzyme has been intensively studied for decades. Evidence that RubisCO phylogenies are incongruent with those derived from other macromolecules has been accumulating and recent discoveries have driven home this point. Here we review findings regarding RubisCO phylogeny and discuss these in the context of the important biochemical and structural features of the enzyme. The implications for the engineering of improved RubisCO enzymes are considered.
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Affiliation(s)
- G M Watson
- Department of Microbiology and Plant Molecular Biology/Biotechnology Program, Ohio State University, Columbus 43210-1292, USA
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7
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Hernandez JM, Baker SH, Lorbach SC, Shively JM, Tabita FR. Deduced amino acid sequence, functional expression, and unique enzymatic properties of the form I and form II ribulose bisphosphate carboxylase/oxygenase from the chemoautotrophic bacterium Thiobacillus denitrificans. J Bacteriol 1996; 178:347-56. [PMID: 8550452 PMCID: PMC177664 DOI: 10.1128/jb.178.2.347-356.1996] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The cbbL cbbS and cbbM genes of Thiobacillus denitrificans, encoding form I and form II ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), respectively, were found to complement a RubisCO-negative mutant of Rhodobacter sphaeroides to autotrophic growth. Endogenous T. denitrificans promoters were shown to function in R. sphaeroides, resulting in high levels of cbbL cbbS and cbbM expression in the R. sphaeroides host. This expression system provided high levels of both T. denitrificans enzymes, each of which was highly purified. The deduced amino acid sequence of the form I enzyme indicated that the large subunit was closely homologous to previously sequenced form I RubisCO enzymes from sulfur-oxidizing bacteria. The form I T. denitrificans enzyme possessed a very low substrate specificity factor and did not exhibit fallover, and yet this enzyme showed a poor ability to recover from incubation with ribulose 1,5-bisphosphate. The deduced amino acid sequence of the form II T. denitrificans enzyme resembled those of other form II RubisCO enzymes. The substrate specificity factor was characteristically low, and the lack of fallover and the inhibition by ribulose 1,5-bisphosphate were similar to those of form II RubisCO obtained from nonsulfur purple bacteria. Both form I and form II RubisCO from T. denitrificans possessed high KCO2 values, suggesting that this organism might suffer in environments containing low levels of dissolved CO2. These studies present the initial description of the kinetic properties of form I and form II RubisCO from a chemoautotrophic bacterium that synthesizes both types of enzyme.
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Affiliation(s)
- J M Hernandez
- Ohio State Biochemistry Program, Ohio State University, Columbus 43210-1292, USA
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Wang X, Tabita FR. Interaction of inactivated and active ribulose 1,5-bisphosphate carboxylase/oxygenase of Rhodobacter sphaeroides with nucleotides and the chaperonin 60 (GroEL) protein. J Bacteriol 1992; 174:3607-11. [PMID: 1350585 PMCID: PMC206048 DOI: 10.1128/jb.174.11.3607-3611.1992] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Purified inactivated form I ribulose 1,5-bisphosphate carboxylase/oxygenase (form I RubisCO) of Rhodobacter sphaeroides was activated by ATP and, to some extent, by other adenylates and nucleotides. Reactivation in the presence of ATP occurred by a time-dependent and concentration-dependent process which appeared to be irreversible. The carbamylated form of inactivated form I RubisCO was less susceptible to ATP-mediated reactivation than the uncarbamylated inactivated enzyme. In some cases, ATP analogs could mimic the reactivation process; one analog, adenylyl(beta, gamma-methylene)-diphosphonate, was found to partially block ATP-mediated reactivation but could not block reactivation induced by Mg(II). Concomitant with the recovery of enzymatic activity, the migration of the inactivated form I RubisCO on nondenaturing and sodium dodecyl sulfate gels changed from a pattern that was characteristic of inactivated enzyme to a pattern that was identical to that of the active protein. It was further found that discrete proportions of active enzyme and the chaperonin 60 protein of R. sphaeroides aggregated in the presence of ATP. The form I RubisCO is thus proposed to contain a specific ATP-binding site that may contribute to both the regulation of activity and the assembly of active enzyme.
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Affiliation(s)
- X Wang
- Department of Microbiology, Biotechnology Center, Ohio State University, Columbus 43210
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9
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Lee BG, Read BA, Tabita FR. Catalytic properties of recombinant octameric, hexadecameric, and heterologous cyanobacterial/bacterial ribulose- 1,5-bisphosphate carboxylase/oxygenase. Arch Biochem Biophys 1991; 291:263-9. [PMID: 1952939 DOI: 10.1016/0003-9861(91)90133-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The recent isolation of a catalytically competent recombinant octameric core of the hexadecameric ribulose-1,5-bisphosphate carboxylase/oxygenase from the cyanobacterium Anacystis nidulans (Synechococcus) (B. Lee and F. R. Tabita, 1990, Biochemistry 29, 9352-9357) has provided a useful system for examining the properties of this enzyme in the absence of small subunits. Unlike most sources of hexadecameric ribulose bisphosphate carboxylase, the nonactivated Anacystis holoenzyme was not inhibited markedly by preincubation with ribulose 1,5-bisphosphate. This was also true for the Anacystis octameric core and a heterologous recombinant enzyme that comprised large subunits from Anacystis and small subunits from the bacterium Alcaligenes eutrophus, suggesting that substrate-mediated inactivation is not influenced by small subunits. In addition, the CO2/O2 specificity factor was not affected by the source of the small subunits incorporated into the structure of the hexadecameric protein, in agreement with previous in vitro heterologous reconstitution studies. The activated octameric Anacystis enzyme, however, was significantly more sensitive to inhibition by the phosphorylated effector 6-phosphogluconate than were the hexadecameric Alcaligenes and Anacystis enzymes and the heterologous Anacystis-Alcaligenes hybrid.
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Affiliation(s)
- B G Lee
- Department of Microbiology, Ohio State University, Columbus 43210
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Newman SM, Cattolico RA. Ribulose bisphosphate carboxylase in algae: synthesis, enzymology and evolution. PHOTOSYNTHESIS RESEARCH 1990; 26:69-85. [PMID: 24420459 DOI: 10.1007/bf00047078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/1990] [Accepted: 06/08/1990] [Indexed: 06/03/2023]
Abstract
Studies demonstrating differences in chloroplast structure and biochemistry have been used to formulate hypotheses concerning the origin of algal plastids. Genetic and biochemical experiments indicate that significant variation occurs in ribulose-1,5-bisphosphate carboxylase (Rubisco) when supertaxa of eukaryotic algae are compared. These differences include variations in the organelle location of the genes and their arrangement, mechanism of Rubisco synthesis, polypeptide immunological reactivity and sequence, as well as efficacy of substrate (ribulose bisphosphate and CO2) binding and inhibitor (6-phosphogluconate) action. The structure-function relationships observed among chromophytic, rhodophytic, chlorophytic and prokaryotic Rubisco demonstrate that: (a) similarities among chromophytic and rhodophytic Rubisco exist in substrate/inhibitor binding and polypeptide sequence, (b) characteristic differences in enzyme kinetics and subunit polypeptide structure occur among chlorophytes, prokaryotes and chromophytes/rhodophytes, and (c) there is structural variability among chlorophytic plant small subunit polypeptides, in contrast to the conservation of this polypeptide in chromophytes and rhodophytes. Taxa-specific differences among algal Rubisco enzymes most likely reflect the evolutionary history of the plastid, the functional requirements of each polypeptide, and the consequences of encoding the large and small subunit genes in the same or different organelles.
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Affiliation(s)
- S M Newman
- Department of Botany, University of Washington, 98195, Seattle, WA, USA
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11
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Hallenbeck PL, Lerchen R, Hessler P, Kaplan S. Phosphoribulokinase activity and regulation of CO2 fixation critical for photosynthetic growth of Rhodobacter sphaeroides. J Bacteriol 1990; 172:1749-61. [PMID: 2156801 PMCID: PMC208665 DOI: 10.1128/jb.172.4.1749-1761.1990] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Rhodobacter sphaeroides genome contains two unlinked genetic regions each encoding numerous proteins involved in CO2 fixation which include phosphoribulokinases (prkA and prkB), ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcLS and rbcR) (P. L. Hallenbeck and S. Kaplan, Photosynth. Res. 19:63-71, 1988; F. R. Tabita, Microbiol. Rev. 52:155-189, 1988), and two open reading frames linked to rbcLS and rbcR, namely, cfxA and cfxB, respectively (P. L. Hallenbeck, R. Lerchen, P. Hessler, and S. Kaplan, J. Bacteriol. 172:1736-1748). In this study, we examined the unique role(s) of each phosphoribulokinase activity in the regulation of CO2 fixation. Strains were constructed which contain null mutations in prkA and/or prkB. Studies utilizing these strains suggested that CO2 fixation plays an essential role in attaining the cellular redox balance necessary for photoheterotrophic growth. The presence of an external electron acceptor can negate the requirement for CO2 for photoheterotrophic growth. Each form of phosphoribulokinase and ribulose 1,5-bisphosphate carboxylase/oxygenase was shown to have distinct roles in CO2 metabolism when cells were exposed to extremes in CO2 levels. Evidence is also presented which unequivocally demonstrated that regulation of the expression of the enzymes involved in CO2 metabolism is effective at the transcriptional level. Although the two regions of the DNA involved in CO2 fixation are physically unlinked, each region of the DNA can have a profound effect on the expression of the other region of the DNA.
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Affiliation(s)
- P L Hallenbeck
- Department of Microbiology, University of Texas Medical School, Houston 77225
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Newman SM, Derocher J, Cattolico RA. Analysis of Chromophytic and Rhodophytic Ribulose-1,5-Bisphosphate Carboxylase Indicates Extensive Structural and Functional Similarities among Evolutionarily Diverse Algae. PLANT PHYSIOLOGY 1989; 91:939-46. [PMID: 16667160 PMCID: PMC1062099 DOI: 10.1104/pp.91.3.939] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase (Rubisco) from the algae Olisthodiscus luteus (chromophyte) and Griffithsia pacifica (rhodophyte) are remarkably similar to each other. However, both enzymes differ significantly in the structure and function when compared to Rubisco from green algae and land plants. Analysis of purified Rubisco from O. luteus and G. pacifica indicates that the size of the holoenzyme and stoichiometry of the 55 and 15 kilodalton subunit polypeptides are approximately 550 kilodaltons and eight:eight for both algae. Antigenic determinants are highly conserved between the O. luteus and G. pacifica enzymes and differ from those of the spinach subunit polypeptides. Sequence similarity between the two algal large subunits has been further confirmed by one-dimensional peptide mapping. Substrate ribulose bisphosphate has no effect on the rate of CO(2)/Mg(2+) activation of O. luteus and G. pacifica enzymes which contrasts to the extensive inhibition of spinach Rubisco activation at similar concentrations of this compound. In addition, the Michaelis constant for CO(2) and the inhibition constant for 6-phosphogluconate are similar for the O. luteus and G. pacifica catalyzed carboxylation reaction. Both values are intermediate to those observed for the tight binding spinach enzyme and weak binding prokaryotic (Rhodospirillum rubrum) enzyme. The biochemical similarities documented between O. luteus and G. pacifica may be due to a common evolutionary origin on the chromophytic and rhodophytic chloroplast but could also result from the fact that both subunit polypeptides are chloroplast DNA encoded in these algal taxa.
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Affiliation(s)
- S M Newman
- Botany Department KB-15, University of Washington, Seattle, Washington 98195
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15
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Affiliation(s)
- G A Codd
- Department of Biological Sciences, University of Dundee, UK
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Jouanneau Y, Tabita FR. In vivo regulation of form I ribulose 1,5-bisphosphate carboxylase/oxygenase from Rhodopseudomonas sphaeroides. Arch Biochem Biophys 1987; 254:290-303. [PMID: 3107471 DOI: 10.1016/0003-9861(87)90105-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
When autotrophically grown cells of Rhodopseudomonas (Rhodobacter) sphaeroides were supplied with an organic carbon source, the activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPC/O) decreased 30 to 60%. The extent of inactivation varied depending on the level of derepression of form I and form II RuBPC/O, and on the nature of the organic carbon source, pyruvate being the most effective. Raising the concentration of CO2 in the gas phase of autotrophic cultures brought about a similar loss of RuBPC/O activity. Immunological assays of form I and form II RuBPC/O proteins indicated that the synthesis of both enzymes had been repressed. Moreover, it is demonstrated that the observed loss of RuBP carboxylase activity was due to inactivation of the form I enzyme; the form II RuBPC/O was not affected. The isolated inactivated form I RuBPC/O exhibited a fivefold lower specific activity compared to the active form I enzyme. The inactivation was accompanied by changes in the properties as well as the structure of the form I enzyme. In autotrophic cells, form I RuBPC/O appeared to be associated with a phosphate-containing compound that decreased the enzyme's relative mobility in nondenaturing gels and increased its density in sucrose gradients. Form I RuBPC/O was released from an apparent complex or aggregate upon in vivo inactivation and/or after in vitro heat treatment. The inactive form I enzyme was found to reactivate in vitro by a slow reaction that was accelerated by heat treatment. However, experiments showed no evidence for in vivo reactivation after cells were reexposed to autotrophic conditions (1.5% CO2 in H2). All these data indicate that R. sphaeroides RuBPC/O activity is controlled at the transcriptional and post-transcriptional levels, through regulatory systems that repress the synthesis of form I and form II RuBPC/O and inactivate the predominant form (form I) when the carbon source no longer becomes limiting for growth.
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Affiliation(s)
- G A Codd
- Department of Biological Sciences, Dundee University, UK
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18
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Tabita FR, Gibson JL, Mandy WJ, Quivey RG. Synthesis and Assembly of a Novel Recombinant Ribulose Bisphosphate Carboxylase/Oxygenase. Nat Biotechnol 1986. [DOI: 10.1038/nbt0286-138] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gibson JL, Tabita FR. Structural differences in the catalytic subunits of form I and form II ribulose 1,5-bisphosphate carboxylase/oxygenase from Rhodopseudomonas sphaeroides. J Bacteriol 1985; 164:1188-93. [PMID: 3934140 PMCID: PMC219314 DOI: 10.1128/jb.164.3.1188-1193.1985] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
There are significant differences in the large subunits of form I and form II ribulose 1,5-bisphosphate carboxylase/oxygenase isolated from Rhodopseudomonas sphaeroides. Two-dimensional peptide mapping of carboxymethylated large subunits clearly indicates that there are differences in the primary structure of the two proteins. These results are supported by limited proteolysis with three different proteases and by subsequent analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These data, in conjunction with immunological studies and investigations on the regulation of the two enzymes, support the conclusion that the large subunits of form I and form II ribulose 1,5-bisphosphate carboxylase/oxygenase may be different gene products.
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20
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Weaver KE, Tabita FR. Complementation of a Rhodopseudomonas sphaeroides ribulose bisphosphate carboxylase-oxygenase regulatory mutant from a genomic library. J Bacteriol 1985; 164:147-54. [PMID: 3876330 PMCID: PMC214223 DOI: 10.1128/jb.164.1.147-154.1985] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A genomic library containing HindIII partial digests of Rhodopseudomonas sphaeroides HR DNA was constructed in the broad-host-range cosmid cloning vector pVK102. With a portion of this library as donor in complementation studies with the ribulose 1,5-bisphosphate carboxylase-oxygenase regulatory mutant R. sphaeroides KW25/11, a fragment of DNA which is capable of partially complementing this mutant was isolated. In four independent matings, Aut+ transconjugants which contained a hybrid plasmid carrying the same 28-kilobase-pair insert were isolated. While complemented strains were capable of growing at rates equal to that of the wild type under photoautotrophic conditions, they were not able to match wild-type levels of ribulose 1,5-biphosphate carboxylase-oxygenase activity or of form I ribulose 1,5-bisphosphate carboxylase-oxygenase protein. In addition, there is some indication that recombination may be necessary for optimal complementation to occur. The size of the complementing fragment was further reduced to 2.7 kilobase pairs by using vectors constructed for subcloning.
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Muller ED, Chory J, Kaplan S. Cloning and characterization of the gene product of the form II ribulose-1,5-bisphosphate carboxylase gene of Rhodopseudomonas sphaeroides. J Bacteriol 1985; 161:469-72. [PMID: 3881398 PMCID: PMC214901 DOI: 10.1128/jb.161.1.469-472.1985] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We report the cloning and characterization of the gene product of the gene for the form II ribulose bisphosphate carboxylase from Rhodopseudomonas sphaeroides. We present evidence that the form II enzyme is encoded by a single gene in R. sphaeroides; however, this gene does hybridize to a second chromosomal locus.
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22
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Dijkhuizen L, Harder W. Current views on the regulation of autotrophic carbon dioxide fixation via the Calvin cycle in bacteria. Antonie Van Leeuwenhoek 1984; 50:473-87. [PMID: 6099093 DOI: 10.1007/bf02386221] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The Calvin cycle of carbon dioxide fixation constitutes a biosynthetic pathway for the generation of (multi-carbon) intermediates of central metabolism from the one-carbon compound carbon dioxide. The product of this cycle can be used as a precursor for the synthesis of all components of cell material. Autotrophic carbon dioxide fixation is energetically expensive and it is therefore not surprising that in the various groups of autotrophic bacteria the operation of the cycle is under strict metabolic control. Synthesis of phosphoribulokinase and ribulose-1,5-bisphosphate carboxylase, the two enzymes specifically involved in the Calvin cycle, is regulated via end-product repression. In this control phosphoenolpyruvate most likely has an alarmone function. Studies of the enzymes isolated from various sources have indicated that phosphoribulokinase is the target enzyme for the control of the rate of carbon dioxide fixation via the Calvin cycle through modulation of existing enzyme activity. In general, this enzyme is strongly activated by NADH, whereas AMP and phosphoenolpyruvate are effective inhibitors. Recent studies of phosphoribulokinase in Alcaligenes eutrophus suggest that this enzyme may also be regulated via covalent modification.
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23
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Jordan DB, Ogren WL. Species variation in kinetic properties of ribulose 1,5-bisphosphate carboxylase/oxygenase. Arch Biochem Biophys 1983; 227:425-33. [PMID: 6582802 DOI: 10.1016/0003-9861(83)90472-1] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Several kinetic parameters of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase from different species were measured and compared. The CO2/O2 specificity (VcKo/VoKc) was found to be about 80 in the enzymes from several C3 species and two C4 species. Specificity values of 58 and 70, respectively, were found in enzymes from the C4 plants Setaria italica and Sorghum bicolor. Two enzymes from cyanobacteria had values of about 50. Substitution of Mn2+ for Mg2+ reduced the CO2/O2 specificity by a factor of about 20 for all enzymes except that of Rhodospirillum rubrum, which was reduced by a factor of 10. Values for KMg2+(apparent) measured at 102 microM CO2 were found to vary by a factor of 8 between different RuBP carboxylase/oxygenase enzymes. Enzymes with high KMg2+(apparent) values generally had high Michaelis constants for CO2. The rate of CO2/Mg2+ activation was inhibited by RuBP in all enzymes, although the concentration of RuBP required to inhibit activation in the enzyme from the cyanobacterium Aphanizomenon flos-aquae was increased by an order of magnitude compared to other higher plant structural-type enzymes. The wide variation found in the kinetic properties of RuBP carboxylase/oxygenase isolated from diverse species appears to be determined in part by past evolutionary pressures and the present physicochemical environment in which the enzyme functions.
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Weaver KE, Tabita FR. Isolation and partial characterization of Rhodopseudomonas sphaeroides mutants defective in the regulation of ribulose bisphosphate carboxylase/oxygenase. J Bacteriol 1983; 156:507-15. [PMID: 6313604 PMCID: PMC217861 DOI: 10.1128/jb.156.2.507-515.1983] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Several mutants of Rhodopseudomonas sphaeroides defective in the derepression of the enzyme ribulose 1,5-bisphosphate carboxylase have been isolated by using the unstable Tn5 vectors pJB4JI and pRK340. Transpositional insertion mutants obtained with pJB4JI were demonstrated to be incapable of increasing ribulose 1,5-bisphosphate carboxylase/oxygenase levels when grown on butyrate-bicarbonate medium or under conditions of carbon starvation, whereas the wild-type strain increased activity four- to eightfold. When the wild-type strain was starved for carbon in the presence of chloramphenicol, no derepression was observed. Crude extracts from mutant and wild-type strains had distinct and consistent differences in protein content as observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Chromatographic evidence indicated that mutants were defective in the regulation of only one of the two forms of ribulose 1,5-bisphosphate carboxylase/oxygenase synthesized by R. sphaeroides.
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Andrews T, Abel K. Kinetics and subunit interactions of ribulose bisphosphate carboxylase-oxygenase from the cyanobacterium, Synechococcus sp. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68863-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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