Wu Yazhen, Li Xiaoxiao, Jin Zhengyu, Svensson Birte, Bai Yuxiang
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Research Laboratory for Starch Related Enzyme, Jiangnan University, Wuxi, Jiangsu 214122, China.
International Joint Research Laboratory for Starch Related Enzyme, Jiangnan University, Wuxi, Jiangsu 214122, China; Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
Carbohydr Polym. 2023 Apr 1;305:120520. doi: 10.1016/j.carbpol.2022.120520. Epub 2023 Jan 3.
How to improve the solubility of linear dextrins (LD) and retain their characteristic helix amphiphilic cavities with flexible embedding capability, is a question worth exploring without adding new chemical groups. The strategy presented in this study is to attach a highly flexible (α-1 → 6) glucochain at the reducing end of LD by preparing a new type of dextrin, referred to as single-arm linear dextrin (SLD). In the actual synthesis, an (α-1 → 6) linked oligosaccharide of DP¯ 10.7 (PDI = 1.28) was formed by extension of glucose units onto sucrose (2 M) by using L940W mutant of the glucansucrase GTF180-ΔN firstly. Next using γ-CD as glucosylation donor γ-CGTase extended this (α-1 → 6) glucochain with (α-1 → 4) bonds. SLD is a chimeric glucosaccharide comprising an (α-1 → 4) linked part (DP¯ 10.5) attached to the nonreducing end of an (α-1 → 6) glucochain as verified by enzyme fingerprinting and H NMR. Furthermore, SLD was validated to show greatly improved solubility and dispersibility of resveratrol in water, as indicated by a 3.12-fold enhancement over the solubility in the presence of 0.014 M SLD. This study provided a new strategy for solving the solubility problem of LD and opens possibilities for new design of the fine structure of starch-like materials.
如何在不添加新化学基团的情况下提高线性糊精（LD）的溶解度，并保留其具有灵活嵌入能力的特征螺旋两亲性空腔，是一个值得探索的问题。本研究提出的策略是通过制备一种新型糊精，即单臂线性糊精（SLD），在LD的还原端连接一条高度灵活的（α-1→6）葡糖链。在实际合成中，首先使用葡聚糖蔗糖酶GTF180-ΔN的L940W突变体将葡萄糖单元延伸到蔗糖（2M）上，形成了DP¯10.7（PDI = 1.28）的（α-1→6）连接的寡糖。接下来，使用γ-CD作为糖基化供体，γ-环糊精葡糖基转移酶用（α-1→4）键延伸这条（α-1→6）葡糖链。通过酶指纹图谱和1H NMR验证，SLD是一种嵌合葡糖糖，由连接在（α-1→6）葡糖链非还原端的（α-1→4）连接部分（DP¯10.5）组成。此外，验证表明，SLD能显著提高白藜芦醇在水中的溶解度和分散性，在0.014M SLD存在下，其溶解度比原来提高了3.12倍。本研究为解决LD的溶解度问题提供了一种新策略，并为淀粉样材料精细结构的新设计开辟了可能性。
