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Lookup NU author(s): Professor David XieORCiD
This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Chemical Society, 2019.
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Granule-bound starch synthase I (GBSSI) and starch-branching enzymes I and II (SBEI and SBEII) are crucial enzymes that biosynthesize starches with varied apparent amylose contents and amylopectin branching structure. With a sweet potato (Ipomoea batatas [L.] Lam. cv. Xushu22), this work shows that downregulating GBSSI (for waxy starch) or SBE (for high-amylose starch) activity allowed the formation of new semicrystalline lamellae (named Type II) in sweet potato starch in addition to the widely reported Type I lamellae. Small-angle X-ray scattering (SAXS) results show that, compared with Type I lamellae, Type II lamellae displayed increased average thickness and thickness-distribution width, with thickened amorphous and crystalline components. The size-exclusion-chromatography (SEC) data revealed mainly two enzyme sets, (i) and (ii), synthesizing amylopectin chains. Reducing the GBSSI or SBE activity increased the amounts of amylopectin long chains (degree of polymerization (DP) ≥ 33). Combined SAXS and SEC analyses indicate that parts of these long chains from enzyme set (i) could be confined to Type II lamellae, followed by DP ≤ 32 short chains in Type I lamellae and the rest of the long chains from enzyme sets (i) and (ii) spanning more than a single lamella.
Author(s): Zhang B, Zhou W, Qiao D, Zhang P, Zhao S, Zhang L, Xie F
Publication type: Article
Publication status: Published
Journal: Journal of Agricultural and Food Chemistry
Year: 2019
Volume: 67
Issue: 22
Pages: 6302-6312
Print publication date: 05/06/2019
Online publication date: 29/03/2019
Acceptance date: 29/03/2019
Date deposited: 31/08/2023
ISSN (print): 0021-8561
ISSN (electronic): 1520-5118
Publisher: American Chemical Society
URL: https://doi.org/10.1021/acs.jafc.8b06523
DOI: 10.1021/acs.jafc.8b06523
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