Biochemical and molecular characterization of a levansucrase from Lactobacillus reuteri

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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“…(71,187,219,220), and, to a lesser extent, Lactobacillus spp. (196,211,213), Streptococcus spp. (59,174), and Gluconacetobacter spp.…”

Section: Fructansucrasesmentioning

confidence: 99%

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

Hijum

Kralj

Ozimek

et al. 2006

Microbiol Mol Biol Rev

392

315

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“…Previously, we have characterized the Lactobacillus reuteri strain 121 levansucrase (Lev; E.C. 2.4.1.10) [4] and inulosucrase (Inu; E.C. 2.4.1.9) [5] enzymes, and identified the catalytic triad in both enzymes [6].…”

Section: Introductionmentioning

confidence: 99%

Mutational analysis of the role of calcium ions in the Lactobacillus reuteri strain 121 fructosyltransferase (levansucrase and inulosucrase) enzymes

et al. 2005

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“…Finally, it should be noted that the presence of mobile genetic elements is a common feature in the genetic organization of the DNA region involved in HePS or HoPS synthesis (Bourgoin et al, 1999;Dabour & LaPointe, 2005;Peant et al, 2005;Tieking et al, 2005;van Hijum et al, 2004). It is well known that these elements allow horizontal transfer between different genera.…”

Section: Wwwintechopencommentioning

confidence: 99%

Biosynthesis, Purification and Biotechnological Use of Exopolysaccharides Produced by Lactic Acid Bacteria

Werning¹,

Notararigo²,

Nacher³

et al. 2012

Food Additive

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Biochemical and molecular characterization of a levansucrase from Lactobacillus reuteri

Abstract: (i) the presence of a C-terminal cell-wall-anchoring motif causing similar expression problems in Escherichia coli, (ii) a relatively high optimum temperature for activity for FTF enzymes, and (iii) at 50 6C, kinetics that are best described by the Hill equation.

Cited by 105 publications

References 36 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

Mutational analysis of the role of calcium ions in the Lactobacillus reuteri strain 121 fructosyltransferase (levansucrase and inulosucrase) enzymes

Biosynthesis, Purification and Biotechnological Use of Exopolysaccharides Produced by Lactic Acid Bacteria

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