6LG0

Crystal structure of SbCGTa in complex with UDP

6LG0 の概要

• エントリーDOI: 10.2210/pdb6lg0/pdb
• 分子名称: SbCGTa, URIDINE-5'-DIPHOSPHATE (3 entities in total)
• 機能のキーワード: transferase
• 由来する生物種: Scutellaria baicalensis
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 305430.52

構造登録者

Gao, H.M.,Yun, C.H. (登録日: 2019-12-04, 公開日: 2020-11-18, 最終更新日: 2023-11-22)

主引用文献

Wang, Z.L.,Gao, H.M.,Wang, S.,Zhang, M.,Chen, K.,Zhang, Y.Q.,Wang, H.D.,Han, B.Y.,Xu, L.L.,Song, T.Q.,Yun, C.H.,Qiao, X.,Ye, M.
Dissection of the general two-step di- C -glycosylation pathway for the biosynthesis of (iso)schaftosides in higher plants.
Proc.Natl.Acad.Sci.USA, 117:30816-30823, 2020

PubMed Abstract: Schaftoside and isoschaftoside are bioactive natural products widely distributed in higher plants including cereal crops and medicinal herbs. Their biosynthesis may be related with plant defense. However, little is known on the glycosylation biosynthetic pathway of these flavonoid di--glycosides with different sugar residues. Herein, we report that the biosynthesis of (iso)schaftosides is sequentially catalyzed by two -glycosyltransferases (CGTs), i.e., CGTa for -glucosylation of the 2-hydroxyflavanone aglycone and CGTb for -arabinosylation of the mono--glucoside. The two enzymes of the same plant exhibit high homology but remarkably different sugar acceptor and donor selectivities. A total of 14 CGTa and CGTb enzymes were cloned and characterized from seven dicot and monocot plants, including , , ssp. , and , and the in vivo functions for three enzymes were verified by RNA interference and overexpression. Through transcriptome analysis, we found homologous genes in 119 other plants, indicating this pathway is general for the biosynthesis of (iso)schaftosides. Furthermore, we resolved the crystal structures of five CGTs and realized the functional switch of SbCGTb to SbCGTa by structural analysis and mutagenesis of key amino acids. The CGT enzymes discovered in this paper allow efficient synthesis of (iso)schaftosides, and the general glycosylation pathway presents a platform to study the chemical defense mechanisms of higher plants.

PubMed: 33199630
DOI: 10.1073/pnas.2012745117

実験手法

X-RAY DIFFRACTION (2.998 Å)