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evolution
Cyanobacterium sp.
Cyanobacterium sp. NBRC 102756 belongs to the cyanobacteria that accumulate water-insoluble alpha-glucan similar to amylopectin rather than glycogen, the latter of which is more commonly produced in these organisms. The amylopectin-producing species invariably have three branching enzyme (BE) homologues, BE1, BE2, and BE3, all belonging to the glycoside hydrolase family 13, GH13, phylogenetic tree. The specific activity of BE3 is much lower than those of BE1 and BE2. Isozymes BE1 and BE2 show similar chain-length preference to BEIIb isoform of Oryza sativa, while the catalytic specificity of BE3 is similar to that of Oryza sativa BEI. These results indicate that starch-producing cyanobacteria have both type-I BE (BE3) and type-II BEs (BE1 and BE2) in terms of chain-length preferences, as is the case of plants
evolution
Cyanobacterium sp.
Cyanobacterium sp. NBRC 102756 belongs to the cyanobacteria that accumulate water-insoluble alpha-glucan similar to amylopectin rather than glycogen, the latter ofwhich is more commonly produced in these organisms. The amylopectin-producing species invariably have three branching enzyme (BE) homologues, BE1, BE2, and BE3, all belonging to the glycoside hydrolase family 13, GH13, phylogenetic tree. The specific activity of BE3 is much lower than those of BE1 and BE2. Isozymes BE1 and BE2 show similar chain-length preference to BEIIb isoform of Oryza sativa, while the catalytic specificity of BE3 is similar to that of Oryza sativa BEI. These results indicate that starch-producing cyanobacteria have both type-I BE (BE3) and type-II BEs (BE1 and BE2) in terms of chain-length preferences, as is the case of plants
evolution
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great variation exists as to the preference of branching enzymes of diffeent species for their acceptor chain, either A-chain or B-chain. Phylogenetic tree of alpha-glucan branching enzymes
evolution
great variation exists as to the preference of branching enzymes of diffeent species for their acceptor chain, either A-chain or B-chain. Phylogenetic tree of alpha-glucan branching enzymes
evolution
great variation exists as to the preference of branching enzymes of diffeent species for their acceptor chain, either A-chain or B-chain. Phylogenetic tree of alpha-glucan branching enzymes
evolution
great variation exists as to the preference of branching enzymes of diffeent species for their acceptor chain, either A-chain or B-chain. Phylogenetic tree of alpha-glucan branching enzymes
evolution
great variation exists as to the preference of branching enzymes of diffeent species for their acceptor chain, either A-chain or B-chain. Phylogenetic tree of alpha-glucan branching enzymes
evolution
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great variation exists as to the preference of branching enzymes of different species for their acceptor chain, either A-chain or B-chain. Phylogenetic tree of alpha-glucan branching enzymes
evolution
the branching enzyme is an unusual member of the alpha-amylase family because it has both alpha-1,4-amylase activity and alpha-1,6-transferase activity
evolution
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the enzyme belongs to the glycoside hydrolase family 13, GH13. Phylogenetic analysis groups VvGBE with other Vibrio GBEs and closely related to GBEs of enteric bacteria. VvGBE and Escherichia coli GBE are type I bacterial GBEs and share 57% sequence similarity
evolution
the enzyme belongs to the glycoside hydrolase family GH13
evolution
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Cyanobacterium sp. NBRC 102756 belongs to the cyanobacteria that accumulate water-insoluble alpha-glucan similar to amylopectin rather than glycogen, the latter ofwhich is more commonly produced in these organisms. The amylopectin-producing species invariably have three branching enzyme (BE) homologues, BE1, BE2, and BE3, all belonging to the glycoside hydrolase family 13, GH13, phylogenetic tree. The specific activity of BE3 is much lower than those of BE1 and BE2. Isozymes BE1 and BE2 show similar chain-length preference to BEIIb isoform of Oryza sativa, while the catalytic specificity of BE3 is similar to that of Oryza sativa BEI. These results indicate that starch-producing cyanobacteria have both type-I BE (BE3) and type-II BEs (BE1 and BE2) in terms of chain-length preferences, as is the case of plants
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evolution
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Cyanobacterium sp. NBRC 102756 belongs to the cyanobacteria that accumulate water-insoluble alpha-glucan similar to amylopectin rather than glycogen, the latter of which is more commonly produced in these organisms. The amylopectin-producing species invariably have three branching enzyme (BE) homologues, BE1, BE2, and BE3, all belonging to the glycoside hydrolase family 13, GH13, phylogenetic tree. The specific activity of BE3 is much lower than those of BE1 and BE2. Isozymes BE1 and BE2 show similar chain-length preference to BEIIb isoform of Oryza sativa, while the catalytic specificity of BE3 is similar to that of Oryza sativa BEI. These results indicate that starch-producing cyanobacteria have both type-I BE (BE3) and type-II BEs (BE1 and BE2) in terms of chain-length preferences, as is the case of plants
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evolution
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great variation exists as to the preference of branching enzymes of diffeent species for their acceptor chain, either A-chain or B-chain. Phylogenetic tree of alpha-glucan branching enzymes
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malfunction
inhibitory effects of these hpSBEIIRNA constructs on the expression of SBEIIa and SBEIIb in maize endosperm, levels of ZmSBEII transcription and SBE activity in kernels of transgenic plants, overview. The transgenic maize lines show increased content of amylopectin chains with high-molecular weight compared to decreased low-molecular weight chains
malfunction
mutations of conserved residues in binding sites I and VI have a debilitating effect on the activity of the enzyme
malfunction
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starch from tubers of enzyme overexpressing plants posses an increased degree of amylopectin branching, with more short chains of degree of polymerisation (DP) 6-12 and particularly of DP6. Construction of transgenic lines expressing a GRANULE-BOUND STARCH SYNTHASE (GBSS) RNAi, which exhibit post-transcriptional gene silencing of GBSS and reduced amylose content in the starch. Both transgenic modifications do not affect granule morphology but reduce starch peak viscosity. In starch from SBEII-overexpressing lines, the increased ratio of short to long amylopectin branches facilitates gelatinisation, which occurs at a reduced temperature (by up to 3°C) or lower urea concentration. In contrast, silencing of GBSS increases the gelatinisation temperature by 4°C, and starch requires a higher urea concentration for gelatinisation. In lines with a range of SBEII overexpression, the magnitude of the increase in SBEII activity, reduction in onset of gelatinisation temperature and increase in starch swollen pellet volume are highly correlated, consistent with reports that starch swelling is greatly dependent upon the amylopectin branching pattern
malfunction
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enzyme mutations cause porphyria
metabolism
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key biocatalyst in synthesis of polysaccharides
metabolism
key biocatalyst in synthesis of polysaccharides
metabolism
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starch synthesis
metabolism
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granule-bound proteins involved in amylopectin synthesis are partitioned into the starch granule as a result of their association within protein complexes, and strach synthase IIa plays a crucial role in trafficking starch synthase I and starch branching enzyme IIb into the granule matrix. A mutant starch synthase IIa that has lost catalytic activity and is inable to bind to starch additionally leads to greatly reduced activities of starch synthase I and starch branching enzyme IIb
metabolism
glycogen and starch branching enzymes catalyze the formation of alpha(1->6) linkages in storage polysaccharides by rearrangement of preexisting alpha-glucans. This reaction occurs through the cleavage of alpha(1->4) linkage and transfer in alpha(1->6) of the fragment in non-reducing position. These enzymes define major elements that control the structure of both glycogen and starch
metabolism
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starch synthase and branching enzyme establish the two glycosidic linkages existing in starch. Both enzymes exist as several isoforms. Starch synthase I activity in native PAGE without addition of glucans is dependent on at least one of the two branching enzyme isoforms active in Arabidopsis leaves. This interaction is most likely not based on a physical association of the enzymes. All starch synthase isoforms I-IV are able to interact with branching enzymes and form branched glucans
metabolism
the balance between branching and debranching is crucial for the synthesis of starch, as an excess of branching activity results in the formation of highly branched, water-soluble, poorly crystalline polyglucan
metabolism
the glycogen branching enzyme catalyzes the formation of alpha-1,6-branching points during glycogenesis by cleaving alpha-1,4 bonds and making new alpha-1,6 bonds
metabolism
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the following assembly mechanism is proposed. Polymer synthesis starts with GlgE and its donor substrate, alpha-maltose 1-phosphate, yielding a linear oligomer with a degree of polymerization (of about 16) sufficient for GlgB to introduce a branch. Branching involves strictly intrachain transfer to generate a C chain (the only constituent chain to retain its reducing end), which now bears an A chain (a nonreducing end terminal branch that does not itself bear a branch). GlgE preferentially extends A chains allowing GlgB to act iteratively to generate new A chains emanating from B chains (nonterminal branches that themselves bear a branch). Although extension and branching occur primarily with A chains, the other chain types are sometimes extended and branched such that some B chains (and possibly C chains) bear more than one branch
metabolism
the following assembly mechanism is proposed. Polymer synthesis starts with GlgE and its donor substrate, alpha-maltose 1-phosphate, yielding a linear oligomer with a degree of polymerization (of about 16) sufficient for GlgB to introduce a branch. Branching involves strictly intrachain transfer to generate a C chain (the only constituent chain to retain its reducing end), which now bears an A chain (a nonreducing end terminal branch that does not itself bear a branch). GlgE preferentially extends A chains allowing GlgB to act iteratively to generate new A chains emanating from B chains (nonterminal branches that themselves bear a branch). Although extension and branching occur primarily with A chains, the other chain types are sometimes extended and branched such that some B chains (and possibly C chains) bear more than one branch
metabolism
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the following assembly mechanism is proposed. Polymer synthesis starts with GlgE and its donor substrate, alpha-maltose 1-phosphate, yielding a linear oligomer with a degree of polymerization (of about 16) sufficient for GlgB to introduce a branch. Branching involves strictly intrachain transfer to generate a C chain (the only constituent chain to retain its reducing end), which now bears an A chain (a nonreducing end terminal branch that does not itself bear a branch). GlgE preferentially extends A chains allowing GlgB to act iteratively to generate new A chains emanating from B chains (nonterminal branches that themselves bear a branch). Although extension and branching occur primarily with A chains, the other chain types are sometimes extended and branched such that some B chains (and possibly C chains) bear more than one branch
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metabolism
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the following assembly mechanism is proposed. Polymer synthesis starts with GlgE and its donor substrate, alpha-maltose 1-phosphate, yielding a linear oligomer with a degree of polymerization (of about 16) sufficient for GlgB to introduce a branch. Branching involves strictly intrachain transfer to generate a C chain (the only constituent chain to retain its reducing end), which now bears an A chain (a nonreducing end terminal branch that does not itself bear a branch). GlgE preferentially extends A chains allowing GlgB to act iteratively to generate new A chains emanating from B chains (nonterminal branches that themselves bear a branch). Although extension and branching occur primarily with A chains, the other chain types are sometimes extended and branched such that some B chains (and possibly C chains) bear more than one branch
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metabolism
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key biocatalyst in synthesis of polysaccharides
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physiological function
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the synthesis of maltodextrins by alpha-glucan phosphorylase Pho1 is markedly accelerated by branching enzyme isozymes, with the greatest effect being exhibited by the presence of branching isozyme BEI rather than by isozyme BEIIa or isozyme BEIIb. The enhancement of the activity of Pho1 by branching enzymes is not merely due to the supply of a non-reducing ends. At the same time, Pho1 greatly enhances the branching enzyme activity, possibly by generating a branched carbohydrate substrate which is used by branching enzyme with a higher affinity. The interaction between Pho1 and branching enzyme is not merely due to chain-elongating and chain-branching reactions, but occurs in a physically and catalytically synergistic manner by each activating the mutual capacity of the other, presumably forming a physical association of Pho1, isoform BEI and branched maltodextrins
physiological function
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glycogen is a major polysaccharide of energy reservoir in animals and microorganisms. It is a highly branched polysaccharide, in which glucose residues are linked by alpha-1,4 glycosidic bonds to from linear chains and at every 10 residues, other linear chains are linked by alpha-1,6-glycosidic bonds to form side chains. Formation of side chains in glycogen is catalyzed by glycogen branching enzyme (GBE) or branching enzyme (BE). GBE catalyzes formation of alpha-1,6-glycosidic linkage by cleaving alpha-1,4 linkages of substrate and transferring the non-reducing end of the chain to an acceptor
physiological function
rice branching enzyme isozymes BEI, BEIIa, or BEIIb accelerate the reaction velocity of starch synthase SSI, but not of SSIIa or SSIIIa, in rice. The interaction between starch synthase I (SSI) and branching enzyme (BE) is established by stimulation of SSI activity with BE and by activation of the BE activity by SSI
physiological function
SBE is the only enzyme that generates glucan branches, i.e. it is the only chain-stopping substance for branch growth, and as a consequence SBE has a significant effect on the final structure of the resulting starch
physiological function
starch branching enzyme IIb plays a crucial role in amylopectin biosynthesis in maize endosperm by defining the structural and functional properties of storage starch and is regulated by protein phosphorylation
physiological function
starch synthesis requires several enzymatic activities including branching enzymes (BEs) responsible for the formation of alpha(1->6) linkages. Distribution and number of these linkages are further controlled by debranching enzymes that cleave some of them, rendering the polyglucan water-insoluble and semi-crystalline. The activity of BEs and debranching enzymes is mandatory to sustain normal starch synthesis
physiological function
the branching enzyme is responsible for all branching of glycogen and starch. It has both alpha-1,4-amylase activity and alpha-1,6-transferase activity
physiological function
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the enzyme GlgB is essential for the biosynthesis of branched glucan and modulates pathogenesis and survival, it is the key enzyme involved in the biosynthesis of alpha-glucan, which plays a significant role in the virulence and pathogenesis of Mycobacterium tuberculosis
physiological function
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the enzyme is a regulator of iron homeostasis. The enzyme interacts physically with the holoform of iron regulatory protein 1A (IRP1A) and Cisd2, an ortholog of vertebrate mitoNEET. This synergistic interaction ensures that holo-IRP1A remains functional
physiological function
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starch branching enzyme IIb plays a crucial role in amylopectin biosynthesis in maize endosperm by defining the structural and functional properties of storage starch and is regulated by protein phosphorylation
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additional information
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branching patterns of the truncation mutants and the swapping mutant. Branching patterns of VvGBE wild-type
additional information
molecular dynamics simulation and modeling of phosphorylation of enzyme mutants
additional information
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molecular dynamics simulation and modeling of phosphorylation of enzyme mutants
additional information
six distinct oligosaccharide binding sites on the surface of the branching enzyme, most of which surround the edge of the beta-barrel domain and are quite far from the active site. No evidence of oligosaccharide binding in the active site of the enzyme, the closest bound oligosaccharide resides almost 18 A from the active site
additional information
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six distinct oligosaccharide binding sites on the surface of the branching enzyme, most of which surround the edge of the beta-barrel domain and are quite far from the active site. No evidence of oligosaccharide binding in the active site of the enzyme, the closest bound oligosaccharide resides almost 18 A from the active site
additional information
the branching enzyme's origin has only a limited impact on establishing essential characteristics of starch
additional information
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the branching enzyme's origin has only a limited impact on establishing essential characteristics of starch
additional information
Tyr352, Glu513, and Ser349 are important for mSBEIIa activity while Arg456 is important for determining the position at which the linear glucan is cut, enzyme active site structure, molecular dynamics simulations and modeling, overview
additional information
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Tyr352, Glu513, and Ser349 are important for mSBEIIa activity while Arg456 is important for determining the position at which the linear glucan is cut, enzyme active site structure, molecular dynamics simulations and modeling, overview
additional information
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molecular dynamics simulation and modeling of phosphorylation of enzyme mutants
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