Structural characterization of the maltose acceptor-products synthesized by Leuconostoc mesenteroides NRRL B-1299 dextransucrase

Dols, M. J. L.; Simeon, Magali Remaud; Willemot, René‐Marc; Vignon, M.R.; Monsan, Pierre

doi:10.1016/s0008-6215(97)10063-5

Cited by 64 publications

(37 citation statements)

References 25 publications

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“…Analysis of the three-dimensional structural information for amylosucrase proteins (GH13) with bound sucrose and oligosaccharide substrates and products provided convincing evidence for the use of a non-reducing-end elongation mechanism (3). Various studies of product formation by GS enzymes incubated with sucrose and acceptor substrates showed (e.g., conversion of maltose into panose by GTFA of L. reuteri [121]) that GS also use sucrose to elongate their oligosaccharide acceptor substrates at the nonreducing end (5,42,95,99,121,130). Mutant data for GTFA of L. reuteri 121 showed similar changes in glucosidic bond specificity with both oligosaccharide and polysaccharide products (96).…”

Section: Kyq Repeat 95mentioning

confidence: 94%

“…Where studied, glucosidic bond specificity observed in polymers is also retained in the oligosaccharides synthesized by these GS enzymes in their acceptor reaction (32,42,99).…”

Section: Reactions Catalyzed and Glucan Product Synthesismentioning

confidence: 99%

“…Koepsell et al (89) observed that in the presence of sucrose and saccharide acceptor substrates such as maltose, isomaltose, and O-␣-methylglucoside, GS enzymes shift from glucan synthesis towards the synthesis of oligosaccharides (the acceptor reaction). Most acceptor reaction studies have been performed using saccharides (5,42,43,53,94,99) or saccharide derivatives as substrates (31,36,150). However, aromatic compounds (e.g., catechine) and salicyl alcohol have also been shown to act as acceptor substrates (114,221).…”

Section: Reactions Catalyzed and Glucan Product Synthesismentioning

confidence: 99%

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Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria

Hijum

Kralj

Ozimek

et al. 2006

Microbiol Mol Biol Rev

393

315

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SUMMARY Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase genes and enzymes from various LAB and their fructan and α-glucan products is reviewed. The GS and FS enzymes are both glycoside hydrolase enzymes that act on the same substrate (sucrose) and catalyze (retaining) transglycosylation reactions that result in polysaccharide formation, but they possess completely different protein structures. GS enzymes (family GH70) are large multidomain proteins that occur exclusively in LAB. Their catalytic domain displays clear secondary-structure similarity with α-amylase enzymes (family GH13), with a predicted permuted (β/α)8 barrel structure for which detailed structural and mechanistic information is available. Emphasis now is on identification of residues and regions important for GS enzyme activity and product specificity (synthesis of α-glucans differing in glycosidic linkage type, degree and type of branching, glucan molecular mass, and solubility). FS enzymes (family GH68) occur in both gram-negative and gram-positive bacteria and synthesize β-fructan polymers with either β-(2→6) (inulin) or β-(2→1) (levan) glycosidic bonds. Recently, the first high-resolution three-dimensional structures have become available for FS (levansucrase) proteins, revealing a rare five-bladed β-propeller structure with a deep, negatively charged central pocket. Although these structures have provided detailed mechanistic insights, the structural features in FS enzymes dictating the synthesis of either β-(2→6) or β-(2→1) linkages, degree and type of branching, and fructan molecular mass remain to be identified.

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Section: Kyq Repeat 95mentioning

confidence: 94%

“…Where studied, glucosidic bond specificity observed in polymers is also retained in the oligosaccharides synthesized by these GS enzymes in their acceptor reaction (32,42,99).…”

Section: Reactions Catalyzed and Glucan Product Synthesismentioning

confidence: 99%

Section: Reactions Catalyzed and Glucan Product Synthesismentioning

confidence: 99%

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Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria

Hijum

Kralj

Ozimek

et al. 2006

Microbiol Mol Biol Rev

393

315

View full text Add to dashboard Cite

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“…In the presence of a maltose acceptor, the glucosyl moiety of sucrose is transferred to maltose at the cost of polymer synthesis. This results in the formation of two different GOS families: the ␣-1,6 GOS series and the ␣-1,2 GOS series (5). The ␣-1,6 GOS series includes linear GOS possessing only ␣-1,6 linkages and a maltose residue at the reducing end.…”

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confidence: 99%

Role of the Two Catalytic Domains of DSR-E Dextransucrase and Their Involvement in the Formation of Highly α-1,2 Branched Dextran

et al. 2005

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The dsrE gene from Leuconostoc mesenteroides NRRL B-1299 was shown to encode a very large protein with two potentially active catalytic domains (CD1 and CD2) separated by a glucan binding domain (GBD). From sequence analysis, DSR-E was classified in glucoside hydrolase family 70, where it is the only enzyme to have two catalytic domains. The recombinant protein DSR-E synthesizes both ␣-1,6 and ␣-1,2 glucosidic linkages in transglucosylation reactions using sucrose as the donor and maltose as the acceptor. To investigate the specific roles of CD1 and CD2 in the catalytic mechanism, truncated forms of dsrE were cloned and expressed in Escherichia coli. Gene products were then small-scale purified to isolate the various corresponding enzymes. Dextran and oligosaccharide syntheses were performed. Structural characterization by 13 C nuclear magnetic resonance and/or high-performance liquid chromatography showed that enzymes devoid of CD2 synthesized products containing only ␣-1,6 linkages. On the other hand, enzymes devoid of CD1 modified ␣-1,6 linear oligosaccharides and dextran acceptors through the formation of ␣-1,2 linkages. Therefore, each domain is highly regiospecific, CD1 being specific for the synthesis of ␣-1,6 glucosidic bonds and CD2 only catalyzing the formation of ␣-1,2 linkages. This finding permitted us to elucidate the mechanism of ␣-1,2 branching formation and to engineer a novel transglucosidase specific for the formation of ␣-1,2 linkages. This enzyme will be very useful to control the rate of ␣-1,2 linkage synthesis in dextran or oligosaccharide production.From sucrose, Leuconostoc mesenteroides NRRL B-1299 produces a very uncommon dextran containing 61% ␣-1,6 glucosidic linkages in the linear chain and 28% ␣-1,2 linkages at branching points (11). The dextransucrase catalyzing the formation of this unusual dextran also produces glucooligosaccharides (GOS) by acceptor reaction. In the presence of a maltose acceptor, the glucosyl moiety of sucrose is transferred to maltose at the cost of polymer synthesis. This results in the formation of two different GOS families: the ␣-1,6 GOS series and the ␣-1,2 GOS series (5). The ␣-1,6 GOS series includes linear GOS possessing only ␣-1,6 linkages and a maltose residue at the reducing end. These oligosaccharides can also be produced by L. mesenteroides NRRL B-512F dextransucrase (12). The ␣-1,2 GOS series consists of ␣-1,6 GOS bearing an additional glucosyl residue linked by an ␣-1,2 linkage at the nonreducing end of the molecule or at the branching points. GOS containing ␣-1,2 linkages are resistant to enzymatic digestion in animals and humans and have been shown to possess prebiotic properties (3,20,22,25). They are commercialized for application in animal and human nutrition, as well as in dermocosmetics.To investigate the mechanism of highly ␣-1,2 branched dextran and GOS formation, three genes from L. mesenteroides

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“…Depending on the glucansucrase-producing strain, the synthesized glucans differ in size and structure. When efficient acceptors, such as maltose or isomaltose, are added to the reaction medium, glucansucrases catalyze the synthesis of low-molecular-weight oligosaccharides and the regiospecificity of several dextransucrases (type of linkages) from the Leuconostoc genus is conserved in oligosaccharide synthesis (8,13,41,45).To date, 17 glucosyltransferase (GTF)-encoding genes from Streptococcus spp., 8 glucansucrase-encoding genes from L. mesenteroides, and 1 gene from Lactobacillus reuteri have been cloned (for reviews, see references 3, 16, 32, and 59). Sequence information shows that they are closely related and share a common structure.…”

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confidence: 99%

Molecular Characterization of DSR-E, an α-1,2 Linkage-Synthesizing Dextransucrase with Two Catalytic Domains

et al. 2002

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A novel Leuconostoc mesenteroides NRRL B-1299 dextransucrase gene, dsrE, was isolated, sequenced, and cloned in Escherichia coli, and the recombinant enzyme was shown to be an original glucansucrase which catalyses the synthesis of ␣-1,6 and ␣-1,2 linkages. The nucleotide sequence of the dsrE gene consists of an open reading frame of 8,508 bp coding for a 2,835-amino-acid protein with a molecular mass of 313,267 Da. This is twice the average mass of the glucosyltransferases (GTFs) known so far, which is consistent with the presence of an additional catalytic domain located at the carboxy terminus of the protein and of a central glucan-binding domain, which is also significantly longer than in other glucansucrases. From sequence comparison with family 70 and ␣-amylase enzymes, crucial amino acids involved in the catalytic mechanism were identified, and several original sequences located at some highly conserved regions in GTFs were observed in the second catalytic domain.Glucansucrase enzymes from oral streptococci, Leuconostoc mesenteroides strains, and some Lactobacillus and Neisseria sp. catalyze the transfer of glucosyl residues from sucrose to synthesize ␣-D-glucopyranosyl homopolymers and oligomers. When sucrose is the sole substrate, high-molecular-weight polymers are obtained. Depending on the glucansucrase-producing strain, the synthesized glucans differ in size and structure. When efficient acceptors, such as maltose or isomaltose, are added to the reaction medium, glucansucrases catalyze the synthesis of low-molecular-weight oligosaccharides and the regiospecificity of several dextransucrases (type of linkages) from the Leuconostoc genus is conserved in oligosaccharide synthesis (8,13,41,45).To date, 17 glucosyltransferase (GTF)-encoding genes from Streptococcus spp., 8 glucansucrase-encoding genes from L. mesenteroides, and 1 gene from Lactobacillus reuteri have been cloned (for reviews, see references 3, 16, 32, and 59). Sequence information shows that they are closely related and share a common structure. These genes code for large enzymes with an average molecular mass of 160,000 Da composed of two main domains: an N-terminal conserved catalytic core of about 900 amino acids and a C-terminal domain covering 300 to 400 residues thought to be responsible for glucan binding and constituted by a series of repeated units (32). In addition, biochemical studies revealed that glucansucrases share many mechanistic features with amylolytic enzymes (15). Structural homologies were later confirmed by amino acid sequence comparison with glucoside hydrolases from family 13 (20). In family 13, the catalytic domain is formed of eight ␤-sheets alternating with eight ␣-helices, conferring a (␤/␣) 8 barrel structure (55). Two structure predictions (9, 26) concluded that glucansucrase enzymes also possess a catalytic (␤/␣) 8 barrel domain. However, MacGregor et al. (26) observed that well-recognized sequence segments appear in a different order, which tends to show that the ␤/␣ barrel elements are circularly permutate...

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Structural characterization of the maltose acceptor-products synthesized by Leuconostoc mesenteroides NRRL B-1299 dextransucrase

Cited by 64 publications

References 25 publications

Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria

Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria

Role of the Two Catalytic Domains of DSR-E Dextransucrase and Their Involvement in the Formation of Highly α-1,2 Branched Dextran

Molecular Characterization of DSR-E, an α-1,2 Linkage-Synthesizing Dextransucrase with Two Catalytic Domains

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