Protein-Bound Ribulose Bisphosphate Correlates with Deactivation of Ribulose Bisphosphate Carboxylase in Leaves

Brooks, Anna; Portis, Archie R.

doi:10.1104/pp.87.1.244

Cited by 74 publications

(65 citation statements)

References 10 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In separate experiments, RuBP levels in the wild-type plants were also measured. In agreement with previous reports examining Arabidopsis (11) and other species (reviewed in ref. 28), the level of RuBP was initially in excess of the level of Rubisco-binding sites under high light.…”

Section: Resultssupporting

confidence: 82%

“…Previous experiments on the wild-type plants have shown that the activation state of Rubisco under normal atmospheric conditions varies with light intensity, ranging from about 40% maximal at very low light to nearly 100% at high light (11). In sharp contrast, the activation state in the rca plants decreases on illumination with either high or low light intensities (27).…”

Section: Resultsmentioning

confidence: 71%

“…In Arabidopsis thaliana and other species, the activity of Rubisco varies with light intensity over the same range as photosynthesis by means of changes in the relative amounts of active and inactive forms of the enzyme (10,11). However, the stromal ADP͞ATP ratio under steady-state conditions does not vary greatly with light intensity (12,13), and a signaling mechanism for the change in Rubisco activity with light intensity has remained obscure.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Light modulation of Rubisco in Arabidopsis requires a capacity for redox regulation of the larger Rubisco activase isoform

Zhang

Kallis

Ewy

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

192

176

View full text Add to dashboard Cite

The light activation of ribulose-1,5-bisphosphate carboxylase͞ox-ygenase (Rubisco) in vivo requires the presence of Rubisco activase, a nuclear-encoded chloroplast protein that consists of two isoforms arising from alternative splicing in most plants. We examined the function of each isoform by characterizing Rubisco activation in transgenic Arabidopsis plants that express only one or both isoforms, as compared with the wild type. In plants expressing only the shorter isoform, Rubisco activity was as high as in the wild type under saturating light, but the activity was not downregulated at intensities limiting for photosynthesis. In contrast, in plants expressing only the longer isoform, Rubisco activity was down-regulated at limiting light, but the activity was slightly lower and increased much more slowly at saturating light intensities as compared with the wild type. Light regulation of Rubisco similar to that in the wild-type plants was observed in the progeny of a genetic cross of these two transformants in which both isoforms were again present. When the capacity to redox regulate the activity of the larger activase isoform was eliminated by replacement of the critical cysteine residues in the carboxyl-terminal extension unique to this isoform, Rubisco activity in saturating light was similar to the wild type, but the ability of the larger isoform to down-regulate Rubisco activity at limiting light intensities in transgenic plants was almost abolished. These results indicate that the light modulation of Rubisco under limiting light is mainly due to the ability to regulate the activity of Rubisco activase by redox changes in the stroma. P hotosynthetic carbon metabolism is initiated by Rubisco, which combines CO 2 with ribulose 1,5-bisphosphate (RuBP) to form two molecules of phosphoglyeric acid. Both photosynthesis and the activity of Rubisco vary with light intensity, which supplies the energy for regeneration of the RuBP substrate. The changes in the activity of Rubisco are caused by ''activation'' by carbamoylation of a lysine residue and Mg 2ϩ -binding in the active site (1). Activity sufficient for high rates of photosynthesis and growth at atmospheric concentrations of CO 2 depends on the activity of another protein, Rubisco activase (reviewed in refs. 2 and 3). The activase hydrolyzes ATP to promote the dissociation of inhibitory sugar phosphates, which may bind to either the carbamoylated (i.e., CA1P; refs. 4 and 5) or uncarbamoylated (i.e., RuBP; ref. 6) forms, and thus it can maintain Rubisco in an almost fully active form even at otherwise limiting CO 2 concentrations (7,8). ADP is an inhibitor of activase activity, and under typical physiological conditions, activase exhibits half or less of its maximal activity in vitro (9).In Arabidopsis thaliana and other species, the activity of Rubisco varies with light intensity over the same range as photosynthesis by means of changes in the relative amounts of active and inactive forms of the enzyme (10, 11). However, the stromal ADP͞ATP ratio under ste...

show abstract

Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 71%

mentioning

confidence: 99%

See 1 more Smart Citation

Light modulation of Rubisco in Arabidopsis requires a capacity for redox regulation of the larger Rubisco activase isoform

Zhang

Kallis

Ewy

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

192

176

View full text Add to dashboard Cite

show abstract

“…6, 8, and 12), and results from the high affinity of RuBP for the decarbamylated catalytic site (kD = 20 nM) (8). More recently, it has been demonstrated that RuBP can be bound in a noncatalytic fashion to Rubisco in leaves which were exposed to conditions that caused deactivation of the enzyme (3,5,10,23). This bound RuBP is presumably removed by another light-dependent enzyme, Rubisco activase (17).…”

Section: Rubp Levelsmentioning

confidence: 99%

Regulation of Ribulose-1,5-Bisphosphate Carboxylase Activity in Response to Diurnal Changes in Irradiance

Kobza¹,

Seemann²

1989

Plant Physiol.

View full text Add to dashboard Cite

The regulation of ribulose-1,5-bisphosphate (RuBP) carboxylase (Rubisco) activity and metabolite pool sizes in response to natural diumal changes in photon flux density (PFD) was examined in three species (Phaseolus vulgaris, Beta vulgaris, and Spinacia oleracea) known to differ in the mechanisms used for this regulation. Diumal regulation of Rubisco activity in P. vulgaris was primarily the result of metabolism of the naturally occurring tight-binding inhibitor of Rubisco, 2-carboxyarabinitol 1-phosphate (CAIP). In B. vulgaris, the regulation of Rubisco activity was the result of both changes in activation state and CAIP metabolism. In S. oleracea, Rubisco activity was regulated by a combination of changes in activation state and the binding/ release of another tight binding inhibitor, probably RuBP. Despite these different mechanisms for the light regulation of Rubisco activity, the relationship between the in vivo activity of Rubisco and the PFD was the same for all three species. Rates of CAIP metabolism were thus sufficient to allow this mechanism to participate in the diumal regulation of Rubisco activity as PFD changed at its normal rate. Furthermore, under natural conditions this regulatory mechanism was found to be important in controlling Rubisco activity over approximately the same range of PFD as did changes in activation state of the enzyme. Finally, this regulation of Rubisco activity resulted in relatively similar and saturating RuBP pool sizes for photosynthesis at all but the lowest PFD values in all three species.

show abstract

“…After the samples were thawed and centrifuged, the supernatant was neutralized with KOH. RuBP was determined by incorporation of 14C0, into P-glycerate in an assay mixture consisting of 100 mM Tricine (pH 8.1), 10 mM MgCI,, 10 mM NaH14C0,, and 5 pg of activated Rubisco (Brooks and Portis, 1988).…”

Section: Enzyme and Metabolite Assaysmentioning

confidence: 99%

Regulation of Photosynthetic Induction State in High- and Low-Light-Grown Soybean and Alocasia macrorrhiza (L.) G. Don

1995

View full text Add to dashboard Cite

Alocasia (Alocasia macrorrhiza [L.] C . Don) and soybean (Clycine max [L.]) were grown under high or low photon flux density (PFD) conditions to achieve a range of photosynthetic capacities and light-adaptation modes. The COz assimilation rate and in vivo linear electron transport rate (If) were determined over a range of PFDs and under saturating 1-s-duration lightflecks applied at a range of frequencies. At the same mean PFD, the assimilation rate and the Jf were lower under the lightfleck regimes than under constant light. The activation state of two, key enzymes of the photosynthetic carbon reduction cycle pathway, ribulose-l,5-bisphosphate carboxylase/oxygenase (Rubisco) and fructose-l,6-bisphosphatase, and the photosynthetic induction states (ISs) were also found to be lower under flashing as compared to continuous PFD. Under all conditions, the IS measured 120 s after an increase in PFD to constant and saturating values was highly correlated with the Rubisco activation state and stomatal conductances established in the light regime before the increase. Both the fructose-1,6-bisphosphatase and Rubisco activities estabiished in a particular light regime were highly correlated with the mean If in that regime.The relationships between enzyme activation state and and between IS and enzyme activation state were similar i n soybean and Alocasia and were not affected either by growth-light regime, and hence photosynthetic capacity, or by flashing versus constant PFD.The common relationship between the linear jf and the activation state of key enzymes suggests that electron transport may be the determinant of the signal regulating IS, at least to the extent that the IS is controlled by the activation state of key stromal enzymes.The dynamics of photosynthetic regulation are of particular consequence to the efficiency of photosynthetic carbon gain by leaves under the transient sunfleck and shade-light regimes characteristic of plant canopies. In particular, enzymes of the PCR pathway are regulated so that their activity is adequate to utilize the available photochemical potential but without excessive activation that could lead to imbalances in metabolite pools. In addition, g5 is regulated to provide an adequate supply of CO, while preventing excessive water loss. Regulation brings into balance the capacities for RuBP regeneration and utilization, as well as the CO, supply via the stomata, so that no single part of the

show abstract

Protein-Bound Ribulose Bisphosphate Correlates with Deactivation of Ribulose Bisphosphate Carboxylase in Leaves

Abstract: Previous reports indicate that ribulose 1,5-bisphosphate (RuBP) binds very tightly to inactive ribulose bisphosphate carboxylase (rubisco)

Cited by 74 publications

References 10 publications

Light modulation of Rubisco in Arabidopsis requires a capacity for redox regulation of the larger Rubisco activase isoform

Light modulation of Rubisco in Arabidopsis requires a capacity for redox regulation of the larger Rubisco activase isoform

Regulation of Ribulose-1,5-Bisphosphate Carboxylase Activity in Response to Diurnal Changes in Irradiance

Regulation of Photosynthetic Induction State in High- and Low-Light-Grown Soybean and Alocasia macrorrhiza (L.) G. Don

Contact Info

Product

Resources

About