Structural and thermodynamic properties of starches extracted from GBSS and GWD suppressed potato lines

Козлов, С. С.; Blennow, Andreas; Кривандин, А. В.; Yuryev, Vladimir P.

doi:10.1016/j.ijbiomac.2006.11.001

Cited by 91 publications

(127 citation statements)

References 59 publications

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“…C6 phosphorylation triggers C3 phosphorylation by phosphoglucan water dikinase (PWD) (8,10,11). Recent data suggest that C6 phosphorylation fits within the unphosphorylated structure of the amylopectin helix, but C3 phosphorylation imposes significant steric effects and is predicted to induce a conformational change (12)(13)(14)(15). This suggests that GWD-directed C6 phosphorylation promotes local hydration of crystalline lamellae and that PWD-directed C3 phosphorylation induces helix strain.…”

mentioning

confidence: 99%

Structural basis for the glucan phosphatase activity of Starch Excess4

Kooi

Taylor

Pace

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Living organisms utilize carbohydrates as essential energy storage molecules. Starch is the predominant carbohydrate storage molecule in plants while glycogen is utilized in animals. Starch is a water-insoluble polymer that requires the concerted activity of kinases and phosphatases to solubilize the outer surface of the glucan and mediate starch catabolism. All known plant genomes encode the glucan phosphatase Starch Excess4 (SEX4). SEX4 can dephosphorylate both the starch granule surface and soluble phosphoglucans and is necessary for processive starch metabolism. The physical basis for the function of SEX4 as a glucan phosphatase is currently unclear. Herein, we report the crystal structure of SEX4, containing phosphatase, carbohydrate-binding, and C-terminal domains. The three domains of SEX4 fold into a compact structure with extensive interdomain interactions. The C-terminal domain of SEX4 integrally folds into the core of the phosphatase domain and is essential for its stability. The phosphatase and carbohydratebinding domains directly interact and position the phosphatase active site toward the carbohydrate-binding site in a single continuous pocket. Mutagenesis of the phosphatase domain residue F167, which forms the base of this pocket and bridges the two domains, selectively affects the ability of SEX4 to function as a glucan phosphatase. Together, these results reveal the unique tertiary architecture of SEX4 that provides the physical basis for its function as a glucan phosphatase.carbohydrate | Lafora disease | laforin | phosphorylation P lants and animals store carbohydrates as starch and glycogen, respectively. Starch is produced in diurnal cycles and is composed of <10% w∕w amylose and >80% w∕w amylopectin in Arabidopsis thaliana leaves (1). Amylose is a linear molecule composed of glucose moieties linked by α-1,4-glycosidic linkages with very few branches. Amylopectin, which is similar to glycogen, is composed of α-1,4-glycosidic linkages with α-1,6-glycosidic branches, but amylopectin branches are arranged in clusters at regular intervals and the branches form double helices that pack together to form crystalline lamellae (2, 3). The decreased branching and crystalline lamellae of amylopectin are key contributors to the insolubility of starch, while glycogen has more branches and is water-soluble.Starch is a water-insoluble polymer whose surface is inaccessible to most enzymes. Recent work convincingly demonstrates that reversible starch phosphorylation and dephosphorylation is essential for processive starch metabolism (reviewed in refs. 4-7). An essential signal triggering starch catabolism is phosphorylation on the C6 position of glucose moieties on the surface of starch by glucan water dikinase (GWD/R1) (8, 9). C6 phosphorylation triggers C3 phosphorylation by phosphoglucan water dikinase (PWD) (8,10,11). Recent data suggest that C6 phosphorylation fits within the unphosphorylated structure of the amylopectin helix, but C3 phosphorylation imposes significant steric effects and is predicted t...

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mentioning

confidence: 99%

Structural basis for the glucan phosphatase activity of Starch Excess4

Kooi

Taylor

Pace

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…A strongly negative correlation (r = -0.7) was found between phosphate content and amylose content (in Kardal background), which is supported by previous studies (Karim et al, 2007;Kozlov et al, 2007;Noda et al, 2004;Singh et al, 2005;ViksoNielsen et al, 2001). These findings confirmed that amylose/amylopectin ratio plays a role in the regulation of starch phosphate content.…”

supporting

confidence: 86%

“…Previous studies have reported the effect of the down-regulation of GWD1 on starch composition and properties (Kozlov et al, 2007;Vikso-Nielsen et al, 2001); however, these studies were conducted on a small sample size and thus strongly limiting conclusions. Therefore, further study in detail is required.…”

Section: Introductionmentioning

confidence: 98%

Starch meets biotechnology : in planta modification of starch composition and functionalities

Xu¹

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“…This broad scattering peak is reciprocally related to the average thickness of the crystalline-amorphous lamella repeat, [120] which is typically 9-10 nm in size. [121][122][123][124][125] There are several different modelling methods to analyse SAXS data that can provide more information than just this average repeat distance. There is a variety of different paracrystalline models that differ in the number of parameters they attempt to fit.…”

Section: Techniques and Assumptionsmentioning

confidence: 99%

Characterization Methods for Starch-Based Materials: State of the Art and Perspectives

Witt

Gilbert

2013

Aust. J. Chem.

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Improving starch-containing materials, whether food, animal feed, high-tech biomaterials, or engineering plastics, is best done by understanding how biosynthetic processes and any subsequent processing control starch structure, and how this structure controls functional properties. Starch structural characterization is central to this. This review examines how information on the three basic levels of the complex multi-scale structure of starch -individual chains, the branching structure of isolated molecules, and the way these molecules form various crystalline and amorphous arrangements -can be obtained from experiment. The techniques include fluorophore-assisted carbohydrate electrophoresis, multipledetector size-exclusion chromatography, and various scattering techniques (light, X-ray, and neutron). Some examples are also given to show how these data provide mechanistic insight into how biosynthetic processes control the structure and how the various structural levels control functional properties.

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Structural and thermodynamic properties of starches extracted from GBSS and GWD suppressed potato lines

Cited by 91 publications

References 59 publications

Structural basis for the glucan phosphatase activity of Starch Excess4

Structural basis for the glucan phosphatase activity of Starch Excess4

Starch meets biotechnology : in planta modification of starch composition and functionalities

Characterization Methods for Starch-Based Materials: State of the Art and Perspectives

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