Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.2.1.13 (glyceraldehyde-3-phosphate dehydrogenase)
6,511 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chloroplast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is composed of two different subunits, GapA and GapB. cDNA clones containing the entire coding sequences of the cytosolic precursors for GapA from pea and for GapB from pea and spinach have been identified, sequenced and the derived amino acid sequences have been compared to the corresponding sequences from tobacco, maize and mustard. These comparisons show that GapB differs from GapA in about 20% of its amino acid residues and by the presence of a flexible and negatively charged C-terminal extension, possibly responsible for the observed association of the enzyme with chloroplast envelopes in vitro. This C-terminal extension (29 or 30 residues) may be susceptible to proteolytic cleavage thereby leading to a conversion of chloroplast GAPDH isoenzyme I into isoenzyme II. Evolutionary rate comparisons at the amino acid sequence level show that chloroplast GapA and GapB evolve roughly two-fold slower than their cytosolic counterpart GapC. GapA and GapB transit peptides evolve about 10 times faster than the corresponding mature subunits. They are relatively long (68 and 83 residues for pea GapA and spinach GapB respectively) and share a similar amino acid framework with other chloroplast transit peptides.
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PMID:Cloning and sequence analysis of cDNAs encoding the cytosolic precursors of subunits GapA and GapB of chloroplast glyceraldehyde-3-phosphate dehydrogenase from pea and spinach. 256 62

Nucleotide sequences for the nuclear genes encoding chloroplast (GapA and GapB) and cytosolic (GapC) glyceraldehyde-3-phosphate dehydrogenases (GAPDHs) from Arabidopsis thaliana were determined. Comparison of nucleotide sequences indicates that the divergence of chloroplast and cytosolic GAPDH genes preceded the divergence of prokaryotes and eukaryotes. In addition, some intron-exon junctions are conserved among GapB, GapC, and chicken GAPDH genes. These results provide evidence at the molecular level to support the idea that introns existed before the divergence of prokaryotes and eukaryotes.
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PMID:Intron existence predated the divergence of eukaryotes and prokaryotes. 305 2

One step in de novo pyridoxine (vitamin B6) and pyridoxal 5'-phosphate biosynthesis was predicted to be an oxidation catalyzed by an unidentified D-erythrose-4-phosphate dehydrogenase (E4PDH). To help identify this E4PDH, we purified the Escherichia coli K-12 gapA- and gapB-encoded dehydrogenases to homogeneity and tested whether either uses D-erythrose-4-phosphate (E4P) as a substrate. gapA (gap1) encodes the major D-glyceraldehyde-3-phosphate dehydrogenase (GA3PDH). The function of gapB (gap2) is unknown, although it was suggested that gapB encodes a second form of GA3PDH or is a cryptic gene. We found that the gapB-encoded enzyme is indeed an E4PDH and not a second GA3PDH, whereas gapA-encoded GA3PDH used E4P poorly, if at all, as a substrate under the in vitro reaction conditions used in this study. The amino terminus of purified E4PDH matched the sequence predicted from the gapB DNA sequence. Purified E4PDH was a heat-stable tetramer with a native molecular mass of 132 kDa. E4PDH had an apparent Km value for E4P [Kmapp(E4P)] of 0.96 mM, an apparent kcat catalytic constant for E4P [kcatapp(E4P)] of 200 s-1, Kmapp(NAD+) of 0.074 mM, and kcatapp(NAD+) of 169 s-1 in steady-state reactions in which NADH formation was determined. From specific activities in crude extracts, we estimated that there are at least 940 E4PDH tetramer molecules per bacterium growing in minimal salts medium plus glucose at 37 degrees C. Thin-layer chromatography confirmed that the product of the E4PDH reaction was likely the aldonic acid 4-phosphoerythronate. To establish a possible role of E4PDH in pyridoxal 5'-phosphate biosynthesis, we showed that 4-phosphoerythronate is a likely substrate for the 2-hydroxy-acid dehydrogenase encoded by the pdxB gene. Implications of these findings in the evolution of GA3PDHs are also discussed. On the basis of these results, we propose renaming gapB as epd (for D-erythrose-4-phosphate dehydrogenase).
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PMID:Biochemical characterization of gapB-encoded erythrose 4-phosphate dehydrogenase of Escherichia coli K-12 and its possible role in pyridoxal 5'-phosphate biosynthesis. 775 Dec 90

Using a PCR-generated homologous probe, we have recovered a cDNA (GapA cDNA) encoding the complete 338 amino-acid chloroplast GAPDH of the marine red alga Gracilaria verrucosa, together with its 78 amino-acid transit peptide. This cDNA was readily aligned with chloroplast-localized GAPDH genes (GapA and GapB) of green plants. The proline residue which contributes to the specificity of NAD+ binding to cytosolic GAPDHs is absent from the deduced polypeptide chain of G. verrucosa GapA as is also the case in the chloroplast GAPDHs of plants. The transit peptide shows a high proportion of random coil, an amino-terminal Met-Ala dipeptide, a high content of hydroxylamino acids, and a net positive charge. The polyadenylation signal appears to be AGTAAA. Genomic Southern-hybridization data indicate that only one chloroplast-GAPDH gene may occur in G. verrucosa. Bootstrapped parsimony trees indicate that the G. verrucosa GapA gene is a sister group to plant chloroplast-GAPDH genes, and are most readily interpreted as showing that red algal and plant chloroplast-localized GAPDHs arose in a single endosymbiotic event.
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PMID:cDNA cloning and characterization of the nuclear gene encoding chloroplast glyceraldehyde-3-phosphate dehydrogenase from the marine red alga Gracilaria verrucosa. 791 71

The single-copy nuclear gene (GapA), encoding the plastid-localized glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of the marine red alga Gracilaria verrucosa, has been cloned and sequenced. The GapA transcriptional initiation site was located 49 bp upstream of the start codon, and a putative TATA box was found 54 bp farther upstream. A spliceosomal intron was identified in the transit-peptide-encoding region in a position very similar to intron 1 of GapA and GapB of higher plants; no introns occur in the region encoding the mature protein. These observations provisionally suggest that both red algae and higher plants descend from a single ancestral photosynthetic eukaryote, i.e. that a single endosymbiotic event gave rise to red algal and higher-plant plastids.
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PMID:Cloning and characterization of the nuclear gene encoding plastid glyceraldehyde-3-phosphate dehydrogenase from the marine red alga Gracilaria verrucosa. 795

Our previous phylogenetic analysis based on cDNA sequences of chloroplast and cytosolic glyceraldehyde-3-phosphate dehydrogenases (GAPDH; genes GapA and GapC, respectively) of the red alga Chondrus crispus suggested that rhodophytes and green plants are sister groups with respect to plastids and mitochondria and diverged at about the same time or somewhat later than animals and fungi. Here we characterize the genomic sequences of genes GapC and GapA of C. crispus with respect to promotor structures, intron/exon organization, genomic complexity, G + C content, CpG suppression and their transcript levels in gametophytes and protoplasts, respectively. To our knowledge this is the first report on nuclear protein genes of red algae. The GapC gene is G + C-rich, contains no introns and displays a number of classic sequence motifs within its promotor region, such as TATA, CAAT, GC boxes and several elements resembling the plant-specific G-box palindrome. The GapA gene has a moderate G+C content, a single CAAT box motif in its promotor region and a single intron of 115 bp near its 5' end. This intron occupies a conserved position corresponding to that of intron 1 in the transit peptide region of chloroplast GAPDH genes (GapA and GapB) of higher plants. It has consensus sequences similar to those of yeast introns and folds into a conspicuous secondary structure of -61.3 kJ. CpG profiles of genes GapC and GapA and their flanking sequences show no significant CpG depletion suggesting that these genomic sequences are not methylated. Genomic Southern blots hybridized with generic and gene specific probes indicate that both genes are encoded by single loci composed of multiple polymorphic alleles. Northern hybridizations demonstrate that both genes are expressed in gametophytes but not in protoplasts where appreciable amounts of transcripts can only be detected for GapC.
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PMID:The GAPDH gene system of the red alga Chondrus crispus: promoter structures, intron/exon organization, genomic complexity and differential expression of genes. 826 Jun 35

We report here effects of three environmental conditions, heat shock, anaerobic treatment, and carbon source supply, on expression of nuclear genes encoding chloroplast (GapA and GapB) and cytosolic (GapC) glyceraldehyde-3-phosphate dehydrogenase from Arabidopsis thaliana. The steady-state mRNA level of the GapC increased when Arabidopsis plants were transferred from normal growth condition to heat-shock, anaerobiosis, or increased sucrose supply conditions. In contrast, the steady-state mRNA levels for GapA and GapB genes were unaffected or decreased transiently under the same treatments. To identify the cis-acting regulatory elements, transgenic tobacco plants containing a 820-bp GapC 5'-flanking DNA fragment and beta-glucuronidase (Gus) fusion were constructed. Analyses of these transgenic plants indicate that this 820-bp DNA fragment is sufficient to confer both heat-shock and anaerobic responses. These results suggest that transcriptional level control is involved in regulation of GapC expression under these stress conditions. Histochemical analysis of Gus activity indicates that expression of the GapC is cell-type specific and is probably linked to the metabolic activity of the cells.
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PMID:Stress responses and metabolic regulation of glyceraldehyde-3-phosphate dehydrogenase genes in Arabidopsis. 827 95

We have characterized the effects of different light spectra on expression of the nuclear genes (GapA and GapB) encoding chloroplast glyceraldehyde-3-phosphate dehydrogenase in Arabidopsis thaliana. Steady-state mRNA levels for both genes in etiolated seedlings increased after a short exposure to red or blue light. However, these increases could not be reversed by immediate far-red light following the initial light treatment. In mature plants, a short light pulse, regardless of its spectrum, had no apparent effect on GapA or GapB mRNA levels in dark-adapted plants. In contrast, continuous exposure to red, blue, or white light resulted in increases of GapA and GapB mRNA levels, with blue and white light being far more efficient than red light. Similarly, continuous exposure of etiolated seedlings to red, blue, or white light also resulted in increased GapA and GapB mRNA levels. In addition, we show that illumination of red light-saturated Arabidopsis plants with continuous blue light results in further increases of GapA and GapB mRNA levels. Based on these results, we conclude that both blue light photoreceptor- and phytochrome-mediated pathways are involved in light regulation of GapA and GapB genes in Arabidopsis, with blue light acting as the dominant regulator.
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PMID:Effects of blue and red light on expression of nuclear genes encoding chloroplast glyceraldehyde-3-phosphate dehydrogenase of Arabidopsis thaliana. 829 Jun 25

Chloroplast NAD(P)-dependent glyceraldehyde-3-phosphate dehydrogenase (NAD(P)-GAPDH; EC 1.2.1.13) consists of two types of subunits: GapA and GapB, which are rather similar, except that GapB carries an unique C-terminal sequence extension. Here, we report evidence that this sequence extension might be responsible for aggregation and dark inactivation of the enzyme in vivo. Recently, it had been demonstrated that upon limited proteolysis of the purified 600 kDa enzyme, using the Staphylococcus aureus V8 endoproteinase (Zapponi et al. (1993) Biol. Chem. Hoppe-Seyler 374, 395-402), the C-terminus of GapB can be removed, giving rise to the 150 kDa form. Based on these findings, we analyzed the changed catalytic properties of the enzyme after proteolysis and its ability to reaggregate. The time-course of proteolysis is paralleled by a strong increase in enzyme activity and the appearance of the tetrameric enzyme form, the increase of apparent activity preceding disaggregation. The proteolyzed enzyme is characterized by its increased affinity towards the substrate 1,3-bisphosphoglycerate and thus resembles the fully activated intact enzyme. In contrast to the effector-mediated activation of the intact enzyme, both proteolytic activation and the resulting disaggregation of the high-molecular-weight form cannot be reversed, even by incubation with NAD.
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PMID:C-terminal truncation of spinach chloroplast NAD(P)-dependent glyceraldehyde-3-phosphate dehydrogenase prevents inactivation and reaggregation. 881 30

Chloroplast glyceraldehyde-3-phosphate dehydrogenase (phosphorylating, E.C. 1.2.1.13) (GAPDH) of higher plants exists as an A2B2 heterotetramer that catalyses the reductive step of the Calvin cycle. In dark chloroplasts the enzyme exhibits a molecular mass of 600 kDa, whereas in illuminated chloroplasts the molecular mass is altered in favor of the more active 150 kDa form. We have expressed in Escherichia coli proteins corresponding to the mature A and B subunits of spinach chloroplast GAPDH (GapA and GapB, respectively) in addition to a derivative of the B subunit lacking the GapB-specific C-terminal extension (CTE). One mg of each of the three proteins so expressed was purified to electrophoretic homogeneity with conventional methods. Spinach GapA purified from E. coli is shown to be a highly active homotetramer (50-70 U/mg) which does not associate under aggregating conditions in vitro to high-molecular-mass (HMM) forms of ca. 600 kDa. Since B4 forms of the enzyme have not been described from any source, we were surprised to find that spinach GapB purified from E. coli was active (15-35 U/mg). Spinach GapB lacking the CTE purified from E. coli is more highly active (130 U/mg) than GapB with the CTE. Under aggregating conditions, GapB lacking the CTE is a tetramer that does not associate to HMM forms whereas GapB with the CTE occurs exclusively as an aggregated HMM form. The data indicate that intertetramer association of chloroplast GAPDH in vitro occurs through GapB-mediated protein-protein interaction.
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PMID:Functional studies of chloroplast glyceraldehyde-3-phosphate dehydrogenase subunits A and B expressed in Escherichia coli: formation of highly active A4 and B4 homotetramers and evidence that aggregation of the B4 complex is mediated by the B subunit carboxy terminus. 898 Apr 99


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