Department of Biological Sciences, KAIST, Daejeon 34141, Republic of Korea; Intelligent Synthetic Biology Center, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea; Systems and Synthetic Biology, Chalmers University of Technology, Göteborg, Sweden.
Department of Biological Sciences, KAIST, Daejeon 34141, Republic of Korea; Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan.
Biotechnol Adv. 2019 Nov 15;37(7):107394. doi: 10.1016/j.biotechadv.2019.04.016. Epub 2019 May 9.
Triterpenoid saponins are naturally occurring structurally diverse glycosides of triterpenes that are widely distributed among plant species. Great interest has been expressed by pharmaceutical and agriculture industries for the glycosylation of triterpenes. Such modifications alter their taste and bio-absorbability, affect their intra-/extracellular transport and storage in plants, and induce novel biological activities in the human body. Uridine diphosphate (UDP)-glycosyltransferases (UGTs) catalyze glycosylation using UDP sugar donors. These enzymes belong to a multigene family and recognize diverse natural products, including triterpenes, as the acceptor molecules. For this review, we collected and analyzed all of the UGT sequences found in Arabidopsis thaliana as well as 31 other species of triterpene-producing plants. To identify potential UGTs with novel functions in triterpene glycosylation, we screened and classified those candidates based on similarity with UGTs from Panax ginseng, Glycine max, Medicago truncatula, Saponaria vaccaria, and Barbarea vulgaris that are known to function in glycosylate triterpenes. We highlight recent findings on UGT inducibility by methyl jasmonate, tissue-specific expression, and subcellular localization, while also describing their catalytic activity in terms of regioselectivity for potential key UGTs dedicated to triterpene glycosylation in plants. Discovering these new UGTs expands our capacity to manipulate the biological and physicochemical properties of such valuable molecules.
三萜皂苷是三萜类天然存在的结构多样的糖苷，广泛分布于植物物种中。制药和农业行业对三萜的糖基化表现出极大的兴趣。这种修饰改变了它们的味道和生物吸收性，影响了它们在植物体内/外的运输和储存，并在人体内诱导新的生物活性。尿苷二磷酸 (UDP)-糖基转移酶 (UGTs) 使用 UDP 糖供体催化糖基化。这些酶属于多基因家族，可识别包括三萜在内的多种天然产物作为受体分子。在本次综述中，我们收集和分析了拟南芥中发现的所有 UGT 序列以及 31 种其他三萜类植物的 UGT 序列。为了鉴定在三萜糖基化中具有潜在新功能的潜在 UGT，我们根据与已知参与三萜糖基化的 Panax ginseng、Glycine max、Medicago truncatula、Saponaria vaccaria 和 Barbarea vulgaris 的 UGT 的相似性对候选 UGT 进行筛选和分类。我们强调了最近关于茉莉酸甲酯诱导的 UGT、组织特异性表达和亚细胞定位的发现，同时还描述了它们在区域选择性方面的催化活性，以用于潜在的专门参与植物三萜糖基化的关键 UGT。发现这些新的 UGT 扩展了我们操纵此类有价值分子的生物学和物理化学性质的能力。
