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Underpinning Starch Biology with in vitro Studies on Carbohydrate-Active Enzymes and Biosynthetic Glycomaterials.

O'Neill EC, Field RA - Front Bioeng Biotechnol (2015)

Bottom Line: Advances are hampered by the challenges inherent in analyzing enzymes that operate across the solid-liquid interface.Glyconanotechnology, in the form of glucan-coated sensor chips and metal nanoparticles, present novel opportunities to address this problem.Herein, we review recent developments aimed at the bottom-up generation and self-assembly of starch-like materials, in order to better understand which enzymes are required for starch granule biogenesis and metabolism.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of Oxford , Oxford , UK.

ABSTRACT
Starch makes up more than half of the calories in the human diet and is also a valuable bulk commodity that is used across the food, brewing and distilling, medicines and renewable materials sectors. Despite its importance, our understanding of how plants make starch, and what controls the deposition of this insoluble, polymeric, liquid crystalline material, remains rather limited. Advances are hampered by the challenges inherent in analyzing enzymes that operate across the solid-liquid interface. Glyconanotechnology, in the form of glucan-coated sensor chips and metal nanoparticles, present novel opportunities to address this problem. Herein, we review recent developments aimed at the bottom-up generation and self-assembly of starch-like materials, in order to better understand which enzymes are required for starch granule biogenesis and metabolism.

No MeSH data available.


Synthesis of 3D glucan structures on the surface of gold nanoparticles. Gold nanoparticles with an immobilized glucan on the surface were imaged with TEM after PHS2-mediated extension with two staining methods (PATAg and UA). As illustrated in the cartoon, the carbohydrate (blue) on the nanoparticles (red), increases after treatment with PHS2 and rearranges to form a thinner layer after 24 h. The schematic shows that the starting glucan (black) is extended by AtPHS2 (blue) and then rearranges by forming intra and inter-chain interactions to produce a more condensed overall structure. Before extension the gold nanoparticles (a) stained weakly with iodine (b), but after PHS2-mediated extension (c) they stained strongly (d), indicating the formation of ordered starch helices. Adapted from O’Neill et al. (2014).
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Figure 2: Synthesis of 3D glucan structures on the surface of gold nanoparticles. Gold nanoparticles with an immobilized glucan on the surface were imaged with TEM after PHS2-mediated extension with two staining methods (PATAg and UA). As illustrated in the cartoon, the carbohydrate (blue) on the nanoparticles (red), increases after treatment with PHS2 and rearranges to form a thinner layer after 24 h. The schematic shows that the starting glucan (black) is extended by AtPHS2 (blue) and then rearranges by forming intra and inter-chain interactions to produce a more condensed overall structure. Before extension the gold nanoparticles (a) stained weakly with iodine (b), but after PHS2-mediated extension (c) they stained strongly (d), indicating the formation of ordered starch helices. Adapted from O’Neill et al. (2014).

Mentions: While a quantifiable 2D system is relevant for kinetic analysis of starch-active enzymes, a third dimension is required to represent the true spatial arrangement of the starch granule. The uniform shape and size and defined physical and chemical properties of gold nanoparticles make them useful materials for the study of biological interactions (Saha et al., 2012). Gold nanoparticles can be simultaneously used to display carbohydrates and to provide visual output of interactions (Marin et al., 2015), using the same photophysical effects exploited in conventional SPR studies, to give a change in color from red to purple. Glucan primers immobilized on gold nanoparticles could be extended substantially by PHS2 (O’Neill et al., 2014). The resulting nanoparticle-based glucan surfaces were subject to aging, with the glucan layer appearing to reorganize and assemble into a much more tightly packed structure over the course of ~12 h (Figure 2). This type of glyconanoparticle has potential for the analysis of enzymes that naturally act on starch granules, and may serve as models for bottom-up, in vitro synthetic biological approaches to biocompatible inorganic surfaces.


Underpinning Starch Biology with in vitro Studies on Carbohydrate-Active Enzymes and Biosynthetic Glycomaterials.

O'Neill EC, Field RA - Front Bioeng Biotechnol (2015)

Synthesis of 3D glucan structures on the surface of gold nanoparticles. Gold nanoparticles with an immobilized glucan on the surface were imaged with TEM after PHS2-mediated extension with two staining methods (PATAg and UA). As illustrated in the cartoon, the carbohydrate (blue) on the nanoparticles (red), increases after treatment with PHS2 and rearranges to form a thinner layer after 24 h. The schematic shows that the starting glucan (black) is extended by AtPHS2 (blue) and then rearranges by forming intra and inter-chain interactions to produce a more condensed overall structure. Before extension the gold nanoparticles (a) stained weakly with iodine (b), but after PHS2-mediated extension (c) they stained strongly (d), indicating the formation of ordered starch helices. Adapted from O’Neill et al. (2014).
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Related In: Results  -  Collection

License
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Figure 2: Synthesis of 3D glucan structures on the surface of gold nanoparticles. Gold nanoparticles with an immobilized glucan on the surface were imaged with TEM after PHS2-mediated extension with two staining methods (PATAg and UA). As illustrated in the cartoon, the carbohydrate (blue) on the nanoparticles (red), increases after treatment with PHS2 and rearranges to form a thinner layer after 24 h. The schematic shows that the starting glucan (black) is extended by AtPHS2 (blue) and then rearranges by forming intra and inter-chain interactions to produce a more condensed overall structure. Before extension the gold nanoparticles (a) stained weakly with iodine (b), but after PHS2-mediated extension (c) they stained strongly (d), indicating the formation of ordered starch helices. Adapted from O’Neill et al. (2014).
Mentions: While a quantifiable 2D system is relevant for kinetic analysis of starch-active enzymes, a third dimension is required to represent the true spatial arrangement of the starch granule. The uniform shape and size and defined physical and chemical properties of gold nanoparticles make them useful materials for the study of biological interactions (Saha et al., 2012). Gold nanoparticles can be simultaneously used to display carbohydrates and to provide visual output of interactions (Marin et al., 2015), using the same photophysical effects exploited in conventional SPR studies, to give a change in color from red to purple. Glucan primers immobilized on gold nanoparticles could be extended substantially by PHS2 (O’Neill et al., 2014). The resulting nanoparticle-based glucan surfaces were subject to aging, with the glucan layer appearing to reorganize and assemble into a much more tightly packed structure over the course of ~12 h (Figure 2). This type of glyconanoparticle has potential for the analysis of enzymes that naturally act on starch granules, and may serve as models for bottom-up, in vitro synthetic biological approaches to biocompatible inorganic surfaces.

Bottom Line: Advances are hampered by the challenges inherent in analyzing enzymes that operate across the solid-liquid interface.Glyconanotechnology, in the form of glucan-coated sensor chips and metal nanoparticles, present novel opportunities to address this problem.Herein, we review recent developments aimed at the bottom-up generation and self-assembly of starch-like materials, in order to better understand which enzymes are required for starch granule biogenesis and metabolism.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of Oxford , Oxford , UK.

ABSTRACT
Starch makes up more than half of the calories in the human diet and is also a valuable bulk commodity that is used across the food, brewing and distilling, medicines and renewable materials sectors. Despite its importance, our understanding of how plants make starch, and what controls the deposition of this insoluble, polymeric, liquid crystalline material, remains rather limited. Advances are hampered by the challenges inherent in analyzing enzymes that operate across the solid-liquid interface. Glyconanotechnology, in the form of glucan-coated sensor chips and metal nanoparticles, present novel opportunities to address this problem. Herein, we review recent developments aimed at the bottom-up generation and self-assembly of starch-like materials, in order to better understand which enzymes are required for starch granule biogenesis and metabolism.

No MeSH data available.