Photoregulation of the biosynthesis of ribulose bisphosphate carboxylase

Development ◽  
1984 ◽  
Vol 83 (Supplement) ◽  
pp. 163-178
Author(s):  
R. John Ellis ◽  
Thomas F. Gallagher ◽  
Gareth I. Jenkins ◽  
C. Ruth Lennox
Keyword(s):  
Chloroplast Development ◽  
Higher Plants ◽  
Large Subunit ◽  
Nuclear Genome ◽  
Small Subunit ◽  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Bisphosphate Carboxylase ◽  
Subunit Mrna ◽  
Parallel Increase

Chloroplast development in higher plants is light dependent, and is accompanied by the synthesis of chlorophyll and the accumulation of many chloroplast polypeptides. There is a 100-fold greater content of the photosynthetic enzyme, ribulose-1,5-bisphosphate carboxylase-oxygenase, in light-grown seedlings of Pisum sativum than in dark-grown seedlings. Following the illumination of dark-grown seedlings, there is a parallel increase in the content of both the mRNA and the polypeptide of the small subunit of the carboxylase; this subunit is a product of the nuclear genome. The increases in the mRNA and the polypeptide of the large subunit, which is a product of the chloroplast genome, show less synchronicity. Studies with isolated leaf nuclei show that the increase in small subunit mRNA is mediated primarily at the level of transcription. Three distinct effects of light on transcription of small subunit genes have been found; a rapid (∼1 h) burst, followed by a decline, when etiolated plants are first exposed to light; a slow (∼36h) development of the competence to transcribe rapidly after the initial burst; rapid (∼20 min) switches in both directions when fully greened plants are exposed to light—dark transitions.

scholarly journals Inhibition of ribulose bisphosphate carboxylase assembly by antibody to a binding protein.

1986 ◽  
Vol 103 (4) ◽  
pp. 1327-1335 ◽  
Author(s):  
S Cannon ◽  
P Wang ◽  
H Roy
Keyword(s):  
Higher Plants ◽  
Binding Protein ◽  
Large Subunit ◽  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Dual Effect ◽  
Bisphosphate Carboxylase ◽  
Low Concentrations ◽  
The One

We have developed an assay to monitor in vitro the posttranslational assembly of the chloroplast protein, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Most of the newly synthesized 55-kD catalytic ("large") subunits of this enzyme occur in a 29S complex together with 60- and 61-kD "binding" proteins. When the 29S complex is incubated with ATP and MgCl2 it dissociates into subunits, and the formerly bound large subunits now sediment at 7S (still faster than expected for a monomer). Upon incubation at 24 degrees C, these large subunits assemble into RuBisCO. The minority of newly made large subunits which are not bound to the 29S complex also sediment at 7S. When endogenous ATP was removed by addition of hexokinase and glucose, the dissociation of the 29S complex was inhibited. Nevertheless, the 7S large subunits assembled into RuBisCO, and did so to a greater extent than in controls retaining endogenous ATP. Thus the 7S large subunits are also assembly competent, at least when ATP is removed. Apparently, in chloroplast extracts, ATP can have a dual effect on the assembly of RuBisCO: on the one hand, even at low concentrations it can inhibit incorporation of 7S large subunits RuBisCO; on the other hand, at higher concentrations it can lead to substantial buildup of the 7S large subunit pool by causing dissociation of the 29S complex, and stimulate overall assembly. At both high and zero concentrations of ATP, however, antibody to the binding protein inhibited the assembly of endogenous large subunits into RuBisCO. Thus it appears that all assembly-competent large subunits are associated with the binding protein, either in the 7S complex or in the 29S complex. The involvement of the binding protein in RuBisCO assembly may represent the first example of non-autonomous protein assembly in higher plants and may pose problems for the genetic engineering of RuBisCO from these organisms.

scholarly journals Maize plastid photogenes: mapping and photoregulation of transcript levels during light-induced development.

1985 ◽  
Vol 100 (2) ◽  
pp. 463-476 ◽  
Author(s):  
S R Rodermel ◽  
L Bogorad
Keyword(s):  
Large Subunit ◽  
Nuclear Gene ◽  
Maximum Size ◽  
Small Subunit ◽  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Bisphosphate Carboxylase ◽  
Transcript Levels ◽  
Expression Control ◽  
Plastid Chromosome

Positively photoregulated regions that show increased transcript levels upon illumination of dark-grown seedlings are scattered over approximately 19% of the maize plastid chromosome. Some photogenes, i.e., genes within these regions, are transcribed individually, whereas others that are transcribed as polycistronic mRNAs appear to be functionally organized into operons. Multiple light-induced transcripts are complementary to most photogenes; these mRNAs are not present in equimolar amounts during plastid photomorphogenesis, but particular transcripts predominate at specific stages of development. Most, but not all, photogene RNA pools reach a maximum size (after either 10, 20, or 44 h of illumination) and then fall to approximately preillumination levels. These data and other considerations argue that photogene expression control is fundamentally transcriptional and that there is more than one expression class. Transcripts of the maize plastid gene for the large subunit of ribulose bisphosphate carboxylase reach a maximum by 20 h of illumination; transcripts of the nuclear gene for the small subunit of this enzyme continue to accumulate and fall considerably later. These data suggest that the level of transcription of the latter gene in the nucleus may be regulated by events in the chloroplast.

The study of plant phylogeny using amino acid sequences of Ribulose-1,5-Bisphosphate carboxylase. I. Patterns of variability

1983 ◽  
Vol 31 (4) ◽  
pp. 395 ◽  
Author(s):  
PG Martin ◽  
AC Jennings
Keyword(s):  
Amino Acids ◽  
Large Subunit ◽  
Small Subunit ◽  
Amino Acid Sequences ◽  
Protein Sequencing ◽  
Ribulose Bisphosphate Carboxylase ◽  
Bisphosphate Carboxylase ◽  
Plant Phylogeny ◽  
Variable Site ◽  
N Terminus

Ribulose bisphosphate carboxylase has been prepared from 50 species of angiosperms from 16 diverse families. In 35 preparations, well known 'bland leaf' methods were used but 15 species had 'pungent leaves' and for these a new preparative method is described. Automatic methods have been used to obtain N-terminal sequences (40 amino acids) of the small subunit (SSU) from all 50 species and the pattern of variability is discussed: 26 of 40 positions are variable to a degree similar to that found in plastocyanin and plant cytochrome c, i.e, an average of 3.7 different amino acids per variable site. These results, and the fact that sufficient protein can be obtained from 100 g of leaves, make a widespread phylogenetic survey of angiosperm SSU feasible and it is claimed that the method is at least as practicable as nucleic acid sequencing. A limited amount of sequencing has been carried out on the large subunit (LSU) but its low variability discourages a protein sequencing survey. Implications for gene structure and function are discussed and evidence is given that active LSU is derived from a precursor with 14 additional amino acids at the N-terminus. In SSU, variability of the two N- terminal amino acids suggests that they are not involved in the signals for removal of either the transit peptide or, in the RNA, of the intron, excision of one end of which depends on the codons for the invariable amino acids at positions 3 and 4. Evidence is also given that if the N-terminus of SSU is methionine, as is common, then it is modified and associated with a 'frayed' N-terminus.

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