Oligosaccharide synthesis by dextransucrase: new unconventional acceptors

Demuth, Kristin; Jördening, Hans‐Joachim; Buchholz, Klaus

doi:10.1016/s0008-6215(02)00272-0

Cited by 52 publications

(17 citation statements)

References 54 publications

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“…Furthermore, after treating the debranched starches with a-amylase, the HPAEC profiles from the transgenic starches were identical to those of KD-UT. These results demonstrate that despite the reported high acceptor efficiency of DSRS (Demuth et al, 2002), dextran chains were not covalently attached to starch, but rather present as separate chains. In general, it can be said that despite altered granule morphology, it is obvious that accumulation of dextran does not interfere with the physicochemical properties and starch content of the transgenic starches.…”

Section: Granule Morphology and Dsrs Expression Are Correlatedmentioning

confidence: 71%

“…This result is consistent with the unchanged physicochemical properties of the transgenic starches. Additionally, it demonstrates that despite the reported high acceptor reaction of DSRS (Demuth et al, 2002), this reaction could not be efficiently carried out inside the amyloplast. Expression of Susy, AGPase and GBSSI genes was slightly negatively affected, due to sucrose conversion of DSRS.…”

Section: Discussionmentioning

confidence: 95%

“…Glucosylation of acceptor molecules such as maltose and isomaltose are the most effective. Interestingly, it was recently shown that the DSRS glucosylation reaction can also be used for the synthesis of new compounds such as oligosaccharide and surfactant derivatives, giving access to novel industrial applications (Demuth et al, 2002;Richard et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…DSRS is targeted to the amyloplast, which has an estimated sucrose concentration of about 10 mM (Farreé t al., 2001). In addition, diversification of starch structures might be envisaged with DSRS, because of its high efficiency in glucosylating acceptor molecules, such as maltose, maltodextrins and starch which are present inside the amyloplast (Demuth et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Production of dextran in transgenic potato plants

et al. 2005

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The production of dextran in potato tubers and its effect on starch biosynthesis were investigated. The mature dextransucrase (DsrS) gene from Leuconostoc mesenteroides was fused to the chloroplastic ferredoxin signal peptide (FD) enabling amyloplast entry, which was driven by the highly tuber-expressed patatin promoter. After transformation of two potato genotypes (cv. Kardal and the amylose-free (amf) mutant), dextrans were detected by enzyme-linked immunosorbent assay (ELISA) in tuber juices of Kardal and amf transformants. The dextran concentration appeared two times higher in the Kardal (about 1.7 mg/g FW) than in the amf transformants. No dextran was detected by ELISA inside the starch granule. Interestingly, starch granule morphology was affected, which might be explained by the accumulation of dextran in tuber juices. In spite of that, no significant changes of the physicochemical properties of the starches were detected. Furthermore, we have observed no clear changes in chain length distributions, despite the known high acceptor efficiency of DSRS.

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Section: Granule Morphology and Dsrs Expression Are Correlatedmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Production of dextran in transgenic potato plants

et al. 2005

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“…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%

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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