Hyung Ko Jae, Gyu Kim Bong, Joong-Hoon Ahn
Division of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, Korea.
FEMS Microbiol Lett. 2006 May;258(2):263-8. doi: 10.1111/j.1574-6968.2006.00226.x.
Microbial glycosyltransferases can convert many small lipophilic compounds such as phenolics, terpenoids, cyanohydrins and alkaloids into glycons using uridine-diphosphate-activated sugars. The main chemical functions of glycosylation processes are stabilization, detoxification and solubilization of the substrates. The gene encoding the UDP-glycosyltransferase from Bacillus cereus, BcGT-1, was cloned by PCR and sequenced. BcGT-1 was expressed in Escherichia coli BL21 (DE3) with a his-tag and purified using a His-tag affinity column. BcGT-1 could use apigenin, genistein, kaempferol, luteolin, naringenin and quercetin as substrates and gave two reaction products. The enzyme preferentially glycosylated at the 3-hydroxyl group, but it could transfer a glucose group onto the 7-hydroxyl group when the 3-hydroxyl group was not available. The reaction products made by biotransformation of flavonoids with E. coli expressing BcGT-1 are similar to those produced with the purified recombinant enzyme. Thus, this work provides a method that might be useful for the biosynthesis of flavonoid glucosides and for the glycosylation of related compounds.
微生物糖基转移酶可以利用尿苷二磷酸激活的糖类，将许多亲脂性小分子化合物，如酚类、萜类、氰醇和生物碱转化为糖苷。糖基化过程的主要化学功能是使底物稳定、解毒和增溶。通过PCR克隆并测序了蜡样芽孢杆菌UDP-糖基转移酶的编码基因BcGT-1。BcGT-1在带有组氨酸标签的大肠杆菌BL21(DE3)中表达，并使用组氨酸标签亲和柱进行纯化。BcGT-1可以使用芹菜素、染料木黄酮、山奈酚、木犀草素、柚皮素和槲皮素作为底物，并产生两种反应产物。该酶优先在3-羟基上进行糖基化，但当3-羟基不可用时，它可以将葡萄糖基团转移到7-羟基上。用表达BcGT-1的大肠杆菌对黄酮类化合物进行生物转化产生的反应产物，与用纯化的重组酶产生的产物相似。因此，这项工作提供了一种可能对黄酮糖苷的生物合成以及相关化合物的糖基化有用的方法。
