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Changes in Nanoscale Chain Assembly in Sweet Potato Starch Lamellae by Downregulation of Biosynthesis Enzymes

Lookup NU author(s): Professor David XieORCiD

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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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Abstract

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.


Publication metadata

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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Funding

Funder referenceFunder name
2018M642865
2662016QD008
31701637
31801582
Chinese Academy of Sciences
China Postdoctoral Science Foundation
Fundamental Research Funds for the Central Universities
National Natural Science Foundation of China
XDPB04

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