Substrate binding sites of Leuconostoc dextransucrase evaluated by inhibition kinetics.

Kobayashi, Mikihiko; Yokoyama, Ikuko; Matsuda, Kazuo

doi:10.1271/bbb1961.50.2585

Cited by 20 publications

(8 citation statements)

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“…Some recent studies based on cloning of glucansucrases encoding gene in addition to the structure-function relationship studies showed two functional domains: a core region involved in sucrose binding and a C-terminal domain involved in glucan-binding [9]. These recent works confirm that glucan-biding site is separated from sucrose biding site as previously suggested [10][11][12].…”

Section: Discussionsupporting

confidence: 69%

The effect of maltose on dextran yield and molecular weight distribution

Rodrigues

Lona

Franco

2005

Bioprocess Biosyst Eng

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Dextran synthesis has been studied since the Second World War, when it was used as blood plasma expander. This polysaccharide composed of glucose units is linked by an alpha-1,6-glucosidic bond. Dextransucrase is a bacterial extra cellular enzyme, which promotes the dextran synthesis from sucrose. When, besides sucrose, another substrate (acceptor) is also present in the reactor, oligosaccharides are produced and part of the glucosyl moieties from glucose is consumed to form these acceptor products, decreasing the dextran yield. Although dextran enzymatic synthesis has been extensively studied, there are few published studies regarding its molecular weight distribution. In this work, the effect of maltose on yield and dextran molecular weight synthesized using dextransucrase from Leuconostoc mesenteroides B512F, was investigated. According to the obtained results, maltose is not able to control and reduce dextran molecular weight distribution and synthesis carried out with or without maltose presented the same molecular weight distribution profile.

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Section: Discussionsupporting

confidence: 69%

The effect of maltose on dextran yield and molecular weight distribution

Rodrigues

Lona

Franco

2005

Bioprocess Biosyst Eng

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“…It has been proposed that glucan is bound to the enzyme through non‐covalent links [38]. More recently, results coming from inhibition kinetic studies using various agents suggested that the glucan binding site was separated from the sucrose binding site [47–51]. This hypothesis has also been confirmed by the identification of glucansucrase sequences and by structure–function relationship studies (see ).…”

Section: Mechanism Of Glucansucrase Actionmentioning

confidence: 89%

“…The necessity of a primer was first accepted in relation to glycogen synthesis mechanism studies carried out at the same period [43]. This hypothesis has been supported by the fact that addition of exogenous glucan has an activating effect on glucan synthesis [50, 52, 53]. However, glucansucrases are active enzymes in the absence of any exogenous primer.…”

Section: Mechanism Of Glucansucrase Actionmentioning

confidence: 99%

Glucansucrases: mechanism of action and structure–function relationships

1999

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Glucansucrases are produced principally by Leuconostoc mesenteroides and oral Streptococcus species, but also by the lactic acid bacteria (Lactococci, Lactobacilli). They catalyse the synthesis of high molecular weight D-glucose polymers, named glucans, from sucrose. In the presence of efficient acceptors, they catalyse the synthesis of low molecular weight oligosaccharides. Glucosidic bond synthesis occurs without the mediation of nucleotide activated sugars and cofactors are not necessary. Glucansucrases have an industrial value because of the production of dextrans and oligosaccharides and a biological importance by their key role in the cariogenic process. They were identified more than 50 years ago. The first glucansucrase encoding gene was cloned more than 10 years ago. But the mechanism of their action remains incompletely understood. However, in order to synthesise oligosaccharides of biological interest or to develop vaccines against dental caries, elucidation of the factors determining the regiospecificity and the regioselectivity of glucansucrases is necessary. The cloning of glucansucrase encoding genes in addition to structure-function relationship studies have allowed the identification of important amino acid residues and have shown that glucansucrases are composed of two functional domains: a core region (ca. 1000 amino acids) involved in sucrose binding and splitting and a C-terminal domain (ca. 500 amino acids) composed of a series of tandem repeats involved in glucan binding. Enzymology studies have enabled different models for their action mechanism to be proposed. The use of secondary structure prediction has led to a clearer knowledge of structure-function relationships of glucansucrases. However, mainly due to the large size of these enzymes, data on the three-dimensional structure of glucansucrases (given by crystallography and modelling) remain necessary to clearly identify those features which determine function.

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“…The precise mechanism of glucansucrases is still not fully understood (Monchois et al, 1999;Robyt, 1995). In the literature, elongation of the glucan chains has been proposed to occur at the non-reducing end (Kobayashi et al, 1986;Mooser et al, 1985) or at the reducing end (Ebert and Schenk, 1968;Robyt et al, 1974).…”

Section: Introductionmentioning

confidence: 99%

Transglycosylation byStreptococcus mutans GS-5 glucosyltransferase-D: Acceptor specificity and engineering of reaction conditions

Meulenbeld

Hartmans²

2000

Biotechnol. Bioeng.

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The acceptor specificity of Streptococcus mutans GS‐5 glucosyltransferase‐D (GTF‐D) was studied, particular the specificity toward non‐saccharide compounds. Dihydroxy aromatic compounds like catechol, 4‐methylcatechol, and 3‐methoxycatechol were glycosylated by GTF‐D with a high efficiency. Transglycosylation yields were 65%, 50%, and 75%, respectively, using 40 mM acceptor and 200 mM sucrose as glucosyl donor. 3‐Methoxylcatchol was also glycosylated, though at a significantly lower rate. A number of other aromatic compounds such as phenol, 2‐hydroxybenzaldehyde, 1,3‐dihydroxybenzene, and 1,2‐phenylethanediol were not glycosylated by GTF‐D. Consequently GTF‐D aromatic acceptors appear to require two adjacent aromatic hydroxyl groups. In order to facilitate the transglycosylation of less water‐soluble acceptors the use of various water miscible organic solvents (cosolvents) was studied. The flavonoid catechin was used as a model acceptor. Bis‐2‐methoxyethyl ether (MEE) was selected as a useful cosolvent. In the presence of 15% (v/v) MEE the specific catechin transglucosylation activity was increased 4‐fold due to a 12‐fold increase in catechin solubility. MEE (10–30% v/v) could also be used to allow the transglycosylation of catechol, 4‐methylcatechol, and 3‐methoxycatechol at concentrations (200 mM) otherwise inhibiting GTF‐D transglycosylation activity. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 70: 363–369, 2000.

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Substrate binding sites of Leuconostoc dextransucrase evaluated by inhibition kinetics.

Cited by 20 publications

References 0 publications

The effect of maltose on dextran yield and molecular weight distribution

The effect of maltose on dextran yield and molecular weight distribution

Glucansucrases: mechanism of action and structure–function relationships

Transglycosylation byStreptococcus mutans GS-5 glucosyltransferase-D: Acceptor specificity and engineering of reaction conditions

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