School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China.
Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
Carbohydr Polym. 2024 Oct 1;341:122297. doi: 10.1016/j.carbpol.2024.122297. Epub 2024 May 20.
The biological activities of heparan sulfate (HS) are intimately related to their molecular weights, degree and pattern of sulfation and homogeneity. The existing methods for synthesizing homogeneous sugar chains of low dispersity involve multiple steps and require stepwise isolation and purification processes. Here, we designed a mesoporous metal-organic capsule for the encapsulation of glycosyltransferase and obtained a microreactor capable of enzymatically catalyzing polymerization reactions to prepare homogeneous heparosan of low dispersity, the precursor of HS and heparin. Since the sugar chain extension occurs in the pores of the microreactor, low molecular weight heparosan can be synthesized through space-restricted catalysis. Moreover, the glycosylation co-product, uridine diphosphate (UDP), can be chelated with the exposed metal sites of the metal-organic capsule, which inhibits trans-cleavage to reduce the molecular weight dispersity. This microreactor offers the advantages of efficiency, reusability, and obviates the need for stepwise isolation and purification processes. Using the synthesized heparosan, we further successfully prepared homogeneous 6-O-sulfated HS of low dispersity with a molecular weight of approximately 6 kDa and a polydispersity index (PDI) of 1.032. Notably, the HS generated exhibited minimal anticoagulant activity, and its binding affinity to fibroblast growth factor 1 was comparable to that of low molecular weight heparins.
硫酸乙酰肝素（HS）的生物学活性与其分子量、硫酸化程度和模式以及均一性密切相关。目前用于合成低分散性均一糖链的方法涉及多个步骤，需要分步进行分离和纯化。在这里，我们设计了一种介孔金属有机胶囊来封装糖基转移酶，并获得了一种能够酶促催化聚合反应以制备低分散性肝素聚糖的微反应器，肝素聚糖是 HS 和肝素的前体。由于糖链的延伸发生在微反应器的孔中，因此可以通过空间受限的催化合成低分子量的肝素聚糖。此外，糖苷化副产物尿苷二磷酸（UDP）可以与金属有机胶囊暴露的金属位点螯合，从而抑制反切割以降低分子量分散度。该微反应器具有高效、可重复使用的优点，并且避免了分步分离和纯化过程的需要。使用合成的肝素聚糖，我们进一步成功制备了低分散性、分子量约为 6 kDa、多分散指数（PDI）为 1.032 的 6-O-硫酸化 HS。值得注意的是，所生成的 HS 抗凝活性最小，其与成纤维细胞生长因子 1 的结合亲和力可与低分子量肝素媲美。
