Cellular Differentiation of Sucrose Metabolism in Anabaena variabilis

Schilling, Norbert; Ehrnsperger, Klaus

doi:10.1515/znc-1985-11-1205

Cited by 36 publications

(50 citation statements)

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“…The data presented herein indicate that these enzymes may be considered responsible for sucrose biosynthesis in Anabaena 7119 as well as in higher plants. In an earlier report, Schilling and Ehrnsperger (23), investigating the biosynthesis and degradation of sucrose in cell-free extracts from A. variabilis, were only able to detect SS activity mainly in vegetative cells. According to their report, SS might be responsible for sucrose synthesis.…”

Section: Discussionmentioning

confidence: 90%

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Sucrose biosynthesis in a prokaryotic organism: Presence of two sucrose-phosphate synthases in Anabaena with remarkable differences compared with the plant enzymes

Porchia¹,

Salerno²

1996

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

103

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Biosynthesis of sucrose-6-P catalyzed by sucrose-phosphate synthase (SPS), and the presence of sucrosephosphate phosphatase (SPP) leading to the formation of sucrose, have both been ascertained in a prokaryotic organism: Anabaena 7119, a filamentous heterocystic cyanobacterium. Two SPS activities (SPS-I and SPS-II) were isolated by ion-exchange chromatography and partially purified. Four remarkable differences between SPSs from Anabaena and those from higher plants were shown: substrate specificity, effect of divalent cations, native molecular mass, and oligomeric composition. Both SPS-I and SPS-II accept Fru-6-P (K m for SPS-I ‫؍‬ 0.8 ؎ 0.1 mM; K m for SPS-II ‫؍‬ 0.7 ؎ 0.1 mM) and UDP-Glc as substrates (K m for SPS-I ‫؍‬ 1.3 ؎ 0.4 mM; K m for SPS-II ‫؍‬ 4.6 ؎ 0.4 mM), but unlike higher plant enzymes, they are not specific for UDP-Glc. GDP-Glc and TDP-Glc are also SPS-I substrates (K m for GDP-Glc ‫؍‬ 1.2 ؎ 0.2 mM and K m for TDP-Glc ‫؍‬ 4.0 ؎ 0.4 mM), and ADP-Glc is used by SPS-II (K m for ADP-Glc ‫؍‬ 5.7 ؎ 0.7 mM). SPS-I has an absolute dependence toward divalent metal ions (Mg 2؉ or Mn 2؉ ) for catalytic activity, not found in plants. A strikingly smaller native molecular mass (between 45 and 47 kDa) was determined by gel filtration for both SPSs, which, when submitted to SDS͞PAGE, showed a monomeric composition. Cyanobacteria are, as far as the authors know, the most primitive organisms that are able to biosynthesize sucrose as higher plants do.

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Section: Discussionmentioning

confidence: 90%

“…However, the biosynthesis of sucrose was not elucidated in photosynthetic prokaryotic organisms even when the accumulation of sucrose was shown in cyanobacteria as a response to salt stress (19)(20)(21)(22) and SS activity was measured in extracts of Anabaena variabilis (23).…”

mentioning

confidence: 99%

Sucrose biosynthesis in a prokaryotic organism: Presence of two sucrose-phosphate synthases in Anabaena with remarkable differences compared with the plant enzymes

Porchia¹,

Salerno²

1996

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

103

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“…The reason why SuSy has only been found in filamentous species of cyanobacteria is unclear. A clue might come from the apparent lack of SPS activity in A. variabilis and the suggestion that SuSy is responsible for Suc synthesis in this species (Schilling and Ehrnsperger, 1985). The equilibrium constant of the SuSy reaction is unfavorable for accumulation of high concentrations of Suc, but if the Suc were being transported out of the vegetative cells into the heterocysts then SuSy could catalyze its net synthesis.…”

Section: Origin and Evolution Of Suc Metabolismmentioning

confidence: 99%

“…However, the relative rates of the forward and reverse reactions catalyzed by SuSy depend on the concentrations of its other reactants, so under certain conditions SuSy could catalyze the net synthesis of Suc. Schilling and Ehrnsperger (1985) found that most SuSy activity is in the vegetative cells of A. variabilis, while the N 2 -fixing heterocysts contain high alkaline invertase activity. Although SPS activity was not detected in either cell type of A. variabilis, Schilling and Ehrnsperger (1985) suggested that Suc is synthesized in the photosynthetic cells by SuSy and transported to the nonphotosynthetic heterocysts to support respiration.…”

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confidence: 97%

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Evolution of Sucrose Synthesis

Lunn

2002

Plant Physiology

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Cyanobacteria and proteobacteria (purple bacteria) are the only prokaryotes known to synthesize sucrose (Suc). Suc-P synthase, Suc-phosphatase (SPP), and Suc synthase activities have previously been detected in several cyanobacteria, and genes coding for Suc-P synthase (sps) and Suc synthase (sus) have been cloned from Synechocystis sp. PCC 6803 and Anabaena (Nostoc) spp., respectively. An open reading frame in the Synechocystis genome encodes a predicted 27-kD polypeptide that shows homology to the maize (Zea mays) SPP. Heterologous expression of this putative spp gene in Escherichia coli, reported here, confirmed that this open reading frame encodes a functional SPP enzyme. The Synechocystis SPP is highly specific for Suc-6 F -P (K m ϭ 7.5 m) and is Mg 2ϩ dependent (K a ϭ 70 m), with a specific activity of 46 mol min Ϫ1 mg Ϫ1 protein. Like the maize SPP, the Synechocystis SPP belongs to the haloacid dehalogenase superfamily of phosphatases/hydrolases. Searches of sequenced microbial genomes revealed homologs of the Synechocystis sps gene in several other cyanobacteria (Nostoc punctiforme, Prochlorococcus marinus strains MED4 and MIT9313, and Synechococcus sp. WH8012), and in three proteobacteria (Acidithiobacillus ferrooxidans, Magnetococcus sp. MC1, and Nitrosomonas europaea). Homologs of the Synechocystis spp gene were found in Magnetococcus sp. MC1 and N. punctiforme, and of the Anabaena sus gene in N. punctiforme and N. europaea. From analysis of these sequences, it is suggested that Suc synthesis originated in the proteobacteria or a common ancestor of the proteobacteria and cyanobacteria.

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Structural and enzymatic analyses of Anabaena heterocyst‐specific alkaline invertase InvB

Xie

Cai

et al. 2018

FEBS Letters

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Anabaena sp. PCC 7120 encodes two alkaline/neutral invertases, namely InvA and InvB. Following our recently reported InvA structure, here we report the crystal structure of the heterocyst-specific InvB. Despite sharing an overall structure similar to InvA, InvB possesses a much higher catalytic activity. Structural comparisons of the catalytic pockets reveal that Arg430 of InvB adopts a different conformation, which may facilitate the deprotonation of the catalytic residue Glu415. We propose that the higher activity may be responsible for the vital role of InvB in heterocyst development and nitrogen fixation. Furthermore, phylogenetic analysis combined with activity assays also suggests the role of this highly conserved arginine in plants and cyanobacteria, as well as some proteobacteria living in highly extreme environments.

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Cellular Differentiation of Sucrose Metabolism in Anabaena variabilis

Cited by 36 publications

References 0 publications

Sucrose biosynthesis in a prokaryotic organism: Presence of two sucrose-phosphate synthases in Anabaena with remarkable differences compared with the plant enzymes

Sucrose biosynthesis in a prokaryotic organism: Presence of two sucrose-phosphate synthases in Anabaena with remarkable differences compared with the plant enzymes

Evolution of Sucrose Synthesis

Structural and enzymatic analyses of Anabaena heterocyst‐specific alkaline invertase InvB

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