甜菊醇
糖苷
化学
甜叶菊
糖基化
糖基转移酶
生物化学
苷元
甜菊苷
雷巴迪甙A
立体化学
酶
食品科学
医学
替代医学
病理
作者
Jinzhu Zhang,Minghai Tang,Yujie Chen,Dan Ke,Jie Zhou,Xinyu Xu,Wenxian Yang,Zihe Li,Haohao Dong,Yuquan Wei,James H. Naismith,Yi Pu Lin,Xiaofeng Zhu,Wei Cheng
标识
DOI:10.1038/s41467-021-27144-4
摘要
Steviol glycosides are the intensely sweet components of extracts from Stevia rebaudiana. These molecules comprise an invariant steviol aglycone decorated with variable glycans and could widely serve as a low-calorie sweetener. However, the most desirable steviol glycosides Reb D and Reb M, devoid of unpleasant aftertaste, are naturally produced only in trace amounts due to low levels of specific β (1-2) glucosylation in Stevia. Here, we report the biochemical and structural characterization of OsUGT91C1, a glycosyltransferase from Oryza sativa, which is efficient at catalyzing β (1-2) glucosylation. The enzyme's ability to bind steviol glycoside substrate in three modes underlies its flexibility to catalyze β (1-2) glucosylation in two distinct orientations as well as β (1-6) glucosylation. Guided by the structural insights, we engineer this enzyme to enhance the desirable β (1-2) glucosylation, eliminate β (1-6) glucosylation, and obtain a promising catalyst for the industrial production of naturally rare but palatable steviol glycosides.
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