A novel 2″-O-galactosyltransferase TcOGT4 was discovered from Trollius chinensis. TcOGT4 could regio-specifically catalyze 2″-O-galactosylation of 17 flavone 8-C-β-d-glucosides and shows high preference for UDP-Gal. Molecular docking indicated that Pro361 may play a key role in sugar donor selectivity, and the P361W mutant exhibited significantly enhanced selectivity toward UDP-Glc. A total of 21 products including 17 new compounds were obtained, and 5 of them showed potent COX-2 inhibitory activities. TcOGT4 is the first reported 2″-O-galactosyltransferase for flavone C-glycosides, and could be a powerful biocatalyst to synthesize bioactive flavone glycosides.

中文翻译：

---

金莲花高选择性2″-O-半乳糖基转移酶的表征及提高UDP-葡萄糖选择性的结构导向工程

从金莲花中发现了一种新的2″ -O-半乳糖基转移酶TcOGT4 。TcOGT4可以区域特异性催化17种黄酮8 -C- β- d-葡萄糖苷的2″ -O-半乳糖基化，并对UDP-Gal表现出高度偏好。分子对接表明Pro361可能在糖供体选择性中起关键作用，P361W突变体对UDP-Glc的选择性显着增强。共获得21个产品，包括17个新化合物，其中5个显示出强效COX-2抑制活性。TcOGT4 是第一个报道的黄酮C的 2″ -O-半乳糖基转移酶-糖苷，并且可能是合成生物活性黄酮糖苷的强大生物催化剂。