Fructan Biosynthetic and Breakdown Enzymes in Dicots Evolved From Different Invertases. Expression of Fructan Genes Throughout Chicory Development

Ende, Wim Van den; Michiels, An; Roover, Joke De; Laere, André Van

doi:10.1100/tsw.2002.288

Cited by 71 publications

(54 citation statements)

References 77 publications

(90 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fructan biosynthesis also is known to occur in plants and fungi and involves a set of enzymes which are evolutionarily related to sucrosehydrolyzing enzymes (invertases). They are clearly different from their bacterial counterparts (75,106,205,216). Although the GS and FS enzymes perform very similar reactions on the same substrates (see below), they do not share a high amino acid sequence similarity, and differ strongly in protein structures.…”

Section: Introductionmentioning

confidence: 98%

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

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.

show abstract

Section: Introductionmentioning

confidence: 98%

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

show abstract

“…Fructans are fructose (Fru)-based oligo- and polysaccharides, representing the major reserve carbohydrates in about 15% of flowering plant species (Hendry, 1993). Fructans can be linear or branched and their degree of polymerization (DP) ranges from three up to a few hundred, depending on the species, developmental stage and environmental conditions (Van den Ende et al, 2002a). Fructans are classified according to differences in glycosidic linkages [β(2,1), β(2,6) or both].…”

Section: Introductionmentioning

confidence: 99%

Multifunctional fructans and raffinose family oligosaccharides

Ende¹

2013

Front. Plant Sci.

199

116

View full text Add to dashboard Cite

Fructans and raffinose family oligosaccharides (RFOs) are the two most important classes of water-soluble carbohydrates in plants. Recent progress is summarized on their metabolism (and regulation) and on their functions in plants and in food (prebiotics, antioxidants). Interest has shifted from the classic inulin-type fructans to more complex fructans. Similarly, alternative RFOs were discovered next to the classic RFOs. Considerable progress has been made in the understanding of structure–function relationships among different kinds of plant fructan metabolizing enzymes. This helps to understand their evolution from (invertase) ancestors, and the evolution and role of so-called “defective invertases.” Both fructans and RFOs can act as reserve carbohydrates, membrane stabilizers and stress tolerance mediators. Fructan metabolism can also play a role in osmoregulation (e.g., flower opening) and source–sink relationships. Here, two novel emerging roles are highlighted. First, fructans and RFOs may contribute to overall cellular reactive oxygen species (ROS) homeostasis by specific ROS scavenging processes in the vicinity of organellar membranes (e.g., vacuole, chloroplasts). Second, it is hypothesized that small fructans and RFOs act as phloem-mobile signaling compounds under stress. It is speculated that such underlying antioxidant and oligosaccharide signaling mechanisms contribute to disease prevention in plants as well as in animals and in humans.

show abstract

“…Three 1-FEHs have recently been cloned from chicory (Van den . It is surprising that in severe contradiction to fructan biosynthetic enzymes that evolved from vacuolar-type invertases, dicot 1-FEHs apparently evolved from cell wall-type invertases (Van den Ende et al, 2002a).…”

mentioning

confidence: 99%

Fructan 1-Exohydrolases. β-(2,1)-Trimmers during Graminan Biosynthesis in Stems of Wheat? Purification, Characterization, Mass Mapping, and Cloning of Two Fructan 1-Exohydrolase Isoforms,

et al. 2003

Self Cite

View full text Add to dashboard Cite

Graminan-type fructans are temporarily stored in wheat (Triticum aestivum) stems. Two phases can be distinguished: a phase of fructan biosynthesis (green stems) followed by a breakdown phase (stems turning yellow). So far, no plant fructan exohydrolase enzymes have been cloned from a monocotyledonous species. Here, we report on the cloning, purification, and characterization of two fructan 1-exohydrolase cDNAs (1-FEH w1 and w2) from winter wheat stems. Similar to dicot plant 1-FEHs, they are derived from a special group within the cell wall-type invertases characterized by their low isoelectric points. The corresponding isoenzymes were purified to electrophoretic homogeneity, and their mass spectra were determined by quadrupole-time-of-flight mass spectrometry. Characterization of the purified enzymes revealed that inulin-type fructans [␤-(2,1)] are much better substrates than levan-type fructans [␤-(2,6)]. Although both enzymes are highly identical (98% identity), they showed different substrate specificity toward branched wheat stem fructans. Although 1-FEH activities were found to be considerably higher during the fructan breakdown phase, it was possible to purify substantial amounts of 1-FEH w2 from young, fructan biosynthesizing wheat stems, suggesting that this isoenzyme might play a role as a ␤-(2,1)-trimmer throughout the period of active graminan biosynthesis. In this way, the species and developmental stage-specific complex fructan patterns found in monocots might be determined by the relative proportions and specificities of both fructan biosynthetic and breakdown enzymes.Starch is the most prominent storage carbohydrate in plants, but about 15% of flowering plant species use fructan (a Fru polymer) as a storage compound (Hendry, 1993). Inulin-type fructan consists of linear ␤-(2,1)-linked fructofuranosyl units and occur mainly in dicotyledonous species. Levan consists of linear ␤-(2,6)-linked fructofuranosyl units, but more complex and branched fructan types (graminan, inulin neoseries, and levan neoseries) are common in monocotyledonous species (Vijn and Smeekens, 1999;Pavis et al., 2001b) Next to their obvious role as reserve compounds, fructan might have other functions in plants like stress protectants (drought and cold) or osmoregulators (Vergauwen et al., 2000; Hincha et al., 2002, and refs. therein). Unlike starch, fructans are water soluble and are believed to be stored in the vacuole , although the exclusive vacuolar localization has been questioned .Although the metabolism of inulin has become clear in dicotyledonous species and the respective biosynthetic and breakdown enzymes have been cloned (Edelman and Jefford, 1968;Van den Ende and Van Laere, 1996a; van der Meer et al., 1998;Hellwege et al., 2000;Van den Ende et al., 2000, fructan metabolism in monocots is not yet completely unraveled. So far, four different fructosyltransferases, each with their own specificity, are believed to be involved in monocot fructan biosynthesis. In addition to inulin biosynthesis by Suc:Suc 1-fructosyl tr...

show abstract

Fructan Biosynthetic and Breakdown Enzymes in Dicots Evolved From Different Invertases. Expression of Fructan Genes Throughout Chicory Development

Cited by 71 publications

References 77 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

Multifunctional fructans and raffinose family oligosaccharides

Fructan 1-Exohydrolases. β-(2,1)-Trimmers during Graminan Biosynthesis in Stems of Wheat? Purification, Characterization, Mass Mapping, and Cloning of Two Fructan 1-Exohydrolase Isoforms,

Contact Info

Product

Resources

About