Diversity of sugar acceptor of glycosyltransferase 1 from Bacillus cereus and its application for glucoside synthesis
Diversity of sugar acceptor of glycosyltransferase 1 from Bacillus cereus and its application for glucoside synthesis
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DOI：
10.1007/s00253-015-7270-1
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发表时间：
2016-05-01
影响因子：
5
通讯作者：
Li, Yaw-Kuen
中科院分区：
文献类型：
--
作者：
Chiu, Hsi-Ho;Shen, Mo-Yuan;Li, Yaw-Kuen
蜡状芽孢杆菌糖基转移酶1(BcGT1)催化尿苷二磷酸葡萄糖(UDP-葡萄糖)向多种受体转移糖基，并对其进行了表达和鉴定。受体的特异性很广：在BcGT1催化下可以合成20多种化合物，包括O-、S-和N-连接的糖苷。基于这项工作，我们得出结论，这些化合物的相应受体必须具有以下特征：(1)受体必须至少含有一个芳香环或稠芳环或杂芳环；(2)反应性羟基、巯基或氨基可以连接在芳环上或其脂肪族侧链上；(3)受体可以是伯胺、仲胺甚至叔胺。4种具有代表性的受体--荧光素甲酯、17-β-雌二醇、7-巯基-4-甲基香豆素和6-苄氨基嘌呤分别被选为O-、S-和N-葡萄糖苷的候选受体。对这些酶产物进行了纯化，其结构经质谱学和核磁共振谱确证。由于所有分离的糖苷都是β-异构体，BcGT1被证实是一种转化酶。本研究不仅证明了BcGT1的底物杂交性，而且展示了该酶在有价值的生物活性分子生物转化中的巨大应用前景。
Glycosyltransferase 1 from Bacillus cereus (BcGT1) catalyzes the transfer of a glucosyl moiety from uridine diphosphate glucose (UDP-glucose) to various acceptors; it was expressed and characterized. The specificity of acceptors was found to be broad: more than 20 compounds classified into O-, S-, and N-linkage glucosides can be prepared with BcGT1 catalysis. Based on this work, we conclude that the corresponding acceptors of these compounds must possess the following features: (1) the acceptors must contain at least one aromatic or fused-aromatic or heteroaromatic ring; (2) the reactive hydroxyl or sulfhydryl or amino group can attach either on the aromatic ring or on its aliphatic side chain; and (3) the acceptors can be a primary, secondary, or even a tertiary amine. Four representative acceptors-fluorescein methyl ester, 17-beta-estradiol, 7-mercapto-4-methylcoumarin, and 6-benzylaminopurine-were chosen as a candidate acceptor for O-, S-, and N-glucosidation, respectively. These enzymatic products were purified and the structures were confirmed with mass and NMR spectra. As all isolated glucosides are beta-anomers, BcGT1 is confirmed to be an inverting enzyme. This study not only demonstrates the substrate promiscuity of BcGT1 but also showed the great application prospect of this enzyme in bioconversion of valuable bioactive molecules.