Glutamate synthase is plastid-encoded in a red alga: implications for the evolution of glutamate synthases

Valentin, Klaus; Kostrzewa, Markus; Zetsche, Klaus

doi:10.1007/bf00021421

Cited by 16 publications

(20 citation statements)

References 58 publications

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“…The remaining 826 bp consists of 720 bp of coding and 20 bp of non-coding upstream sequences. By comparison with the cDNA of other glutamate synthases (Oliver et al, 1987;Sakakibara et al, 1991;Gregerson et al, 1993;Pelanda et al, 1993;Valentin et al, 1993;Navarro et al, 1995), one intron (86 bp), which has the correct splite-site consensus sequence (Goodall and Filipowicz, 1991), was found to be located at nucleotide position 667 of the 720-bp coding sequence. The combined sequence is 5178 bp long, and has a single open reading frame encoding 1648 amino acids of 180090 Da (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The full-length cDNA and structural gene have been cloned for Fd-dependent glutamate synthase in monocot maize (Sakakibara et al, 1991), red alga (Valentin et al, 1993) and cyanobacteria (Navarro et al, 1995), NADH-dependent glutamate synthase in alfalfa nodules (Gregerson et al, 1993) and NADPH-dependent glutamate synthase in bacteria (Oliver et al, 1987;Pelanda et al, 1993).…”

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confidence: 99%

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Structure and Regulation of Ferredoxin‐Dependent Glutamase Synthase from Arabidopsis Thaliana

Suzuki

Rothstein

1997

European Journal of Biochemistry

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Ferredoxin (Fd)-dependent glutamate synthase is present in green leaves, etiolated leaves, shoots and roots of Ambidopsis thaliana (ecotype Columbia). In photosynthetic green leaves and shoots, Fd-dependent glutamate synthase accounts for more than 96% of the total glutamate synthase activity in vitro with the remaining activity derived from an enzyme that uses NADH as the electron donor. In etiolated leaves and roots, Fd-dependent glutamate synthase is 3 -4-fold less active than in green leaves, but represents 70-85 % of the total glutamate synthase activity in these tissues. Fd-dependent glutamate synthase is detected as a single peptide of 165 kDa on a western blot of green leaf and shoot tissues, and this Fddependent glutamate synthase polypeptide is 3 -4-fold less abundant in etiolated leaves and roots. In these non-photosynthetic tissues, there is a higher activity of NADH-dependent glutamate synthase. The A. thaliana gltS mutant (strain CS254) contains only 1.7% and 17.5% of the wild-type Fd-dependent glutamate synthase activity in leaves and roots, respectively. Western blots indicate that the Fd-dependent glutamate synthase peptide of 165 kDa is absent from leaves and roots of the gltS mutant. In contrast, NADH-dependent glutamate synthase activity in leaves and roots is unaffected. During illumination of wild-type dark-grown leaves for 72 h, the levels of Fd-dependent glutamate synthase protein and its activity increased threefold to levels equivalent to those in green leaves. In contrast, NADH-dependent glutamate synthase activity decreases twofold during illumination. The complete nucleotide sequence of the complementary DNA for A. tlzaliana Fd-dependent glutamate synthase has been determined. Analysis of the amino acid sequence deduced from the complete cDNA sequence (5178 bp) has revealed that A. thaliana Fd-dependent glutamate synthase i s synthesized as a 1648-amino-acid precursor protein (I80090 Da) which consists of a 131-amino-acid transit peptide (14603 Da) and a 1517-amino-acid mature peptide (165487 Da). The A. thaliuria Fd-dependent glutamate synthase has a high similarity to maize Fd-dependent glutamate synthase (83 9%) and to the analogous region of NADH-dependent glutamate synthase (42 %) and NADPH-dependent glutamate synthases (40-43 %) from different organisms. The A. thuliaiiu Fd-dependent glutamate synthase contains the purF-type glutamine-amido-transfer domain as well as flavin and iron-sulfur-cluster-binding domains. The deduced primary structures of A. thaliaiza Fd-dependent glutamate synthase and of glutamate synthases from other organisms indicate that Fd-dependent glutamate synthase may have evolved from bacterial NADPH-dependent glutamate synthase. The cDNA hybridized to RNA of about 5.3 kb from different tissues of A. thaliana. A high steadystate level of Fd-dependent glutamate synthase mRNA is found in photosynthetic green leaves and shoots, and roots contain less mRNA for Fd-dependent glutamate synthase. In the gEtS mutant, there are twofold and fourfold lower levels of Fd...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Structure and Regulation of Ferredoxin‐Dependent Glutamase Synthase from Arabidopsis Thaliana

Suzuki

Rothstein

1997

European Journal of Biochemistry

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“…5). (Valentin et al, 1993), maize Fd-GOGAT (Sakakibara et al, 1991), P. boryanum Fd-GOGAT (GlsF) and NADH-GOGAT (GltB and GltD) (this study), alfalfa NADH-GOGAT (Gregerson et al, 1993), Synechocystis sp. PCC 6803 Fd-GOGATs (GltS and GltB) (Navarro et al, 1995), Synechocystis sp.…”

Section: Discussionmentioning

confidence: 50%

Cloning and Inactivation of Genes Encoding Ferredoxin- and NADH-Dependent Glutamate Synthases in the CyanobacteriumPlectonema boryanum. Imbalances in Nitrogen and Carbon Assimilations Caused by Deficiency of the Ferredoxin-Dependent Enzyme1

Okuhara

Matsumura²,

Fujita

et al. 1999

Plant Physiology

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Glutamate synthase (GOGAT) is a key enzyme in the assimilation of inorganic nitrogen in photosynthetic organisms. We found that, like higher plants, the facultative heterotrophic cyanobacterium Plectonema boryanum had ferredoxin (Fd)-and NADH-dependent GOGATs. The genes glsF, gltB, and gltD were cloned, and structural analyses and target mutageneses demonstrated that glsF encoded Fd-GOGAT and that gltB and gltD encoded the two subunits of NADH-GOGAT. All three mutants lacking one of the GOGAT genes were able to grow photosynthetically and heterotrophically. However, the Fd-GOGAT mutant exhibited a phenotype of marked nitrogen deficiency when grown under conditions of saturating illumination and CO 2 supply. In these conditions the rate of the ammonia uptake from the culture medium was slower in the Fd-GOGAT mutant than in the wild type or in the NADH-GOGAT mutant, but no significant differences were found in the rate of the CO 2 fixation-dependent O 2 evolution among these strains. Our results suggest that, although both Fd-and NADH-GOGATs were operative in the cells growing in light, the contribution of Fd-GOGAT, which directly utilizes photoreducing power for the catalytic reaction, is essential for balancing photosynthetic nitrogen and carbon assimilation.Inorganic nitrogen in the form of ammonia is assimilated into Gln and Glu through the combined actions of GS and GOGAT in all oxygenic photosynthetic organisms from cyanobacteria to higher plants ( Lea et al., 1990;Flores and Herrero, 1994). GS catalyzes the ATP-dependent amination of Glu to yield Gln. GOGAT catalyzes the reductive transfer of the amide group of Gln to the keto position of 2-oxoglutarate to yield two molecules of Glu. The resulting Gln and Glu serve as nitrogen donors in the biosynthesis of various nitrogen-containing compounds (Lea et al., 1989).The GS/GOGAT pathway ultimately requires ATP and reducing power generated by photosynthesis and catabolism of carbohydrates and utilizes carbon skeletons provided from intermediates of the TCA cycle, together with the downstream metabolism of Gln and Glu. This pathway is thus involved in the integration of carbon and nitrogen assimilations.In higher plants GOGAT occurs as two distinct forms, one that is Fd dependent (EC1.4.7.1) and one that is NADH dependent (EC 1.4.1.14); the two forms differ in their specificity for an electron donor and in their molecular architecture. cDNAs for both types of GOGAT have been cloned and characterized (Sakakibara et al., 1991;Gregerson et al., 1993), and they were found to be homologous to Escherichia coli NADPH-GOGAT (EC 1.4.1.13), which is composed of two different polypeptides, large and small subunits encoded by gltB and gltD, respectively (Oliver et al., 1987). Fd-GOGAT is an iron-sulfur flavoprotein composed of a single polypeptide that has a molecular mass of 160 kD and is similar to the large subunit of the E. coli enzyme (Sakakibara et al., 1991). NADH-GOGAT is also a single polypeptide but with two domains, the N-terminal, 160-kD and the C-terminal, 60-kD...

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“…Recently, the first three-dimensional structure for a Fd-dependent glutamate synthase has become available (van den Heuvel et al, 2002Heuvel et al, , 2003. Figure 6 shows the structure of the Fd-dependent glutamate synthase from the cyanobacterium Synechocystis sp.…”

Section: B Ferredoxin-dependent Glutamate Synthasementioning

confidence: 99%

“…In most oxygenic photosynthetic eukaryotes the enzymes are encoded by nuclear genes and synthesized as preproteins with N-terminal signal sequences that targets them for delivery to the chloroplast stroma (Suzuki and Knaff, 2005). However, in at least one red alga the enzyme is plastid encoded (Valentin et al, 1993).…”

Section: B Ferredoxin-dependent Glutamate Synthasementioning

confidence: 99%

The Interaction of Ferredoxin with Ferredoxin-Dependent Enzymes

Hase

Schürmann

Knaff

Advances in Photosynthesis and Respiration

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Glutamate synthase is plastid-encoded in a red alga: implications for the evolution of glutamate synthases

Cited by 16 publications

References 58 publications

Structure and Regulation of Ferredoxin‐Dependent Glutamase Synthase from Arabidopsis Thaliana

Structure and Regulation of Ferredoxin‐Dependent Glutamase Synthase from Arabidopsis Thaliana

Cloning and Inactivation of Genes Encoding Ferredoxin- and NADH-Dependent Glutamate Synthases in the CyanobacteriumPlectonema boryanum. Imbalances in Nitrogen and Carbon Assimilations Caused by Deficiency of the Ferredoxin-Dependent Enzyme1

The Interaction of Ferredoxin with Ferredoxin-Dependent Enzymes

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