Crystal structure of SbCGTa in complex with UDP

Experimental Data Snapshot

  • Resolution: 3.00 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.244 

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Dissection of the general two-step di- C -glycosylation pathway for the biosynthesis of (iso)schaftosides in higher plants.

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.

(2020) Proc Natl Acad Sci U S A 117: 30816-30823

  • DOI: https://doi.org/10.1073/pnas.2012745117
  • Primary Citation of Related Structures:  
    6LF6, 6LFN, 6LFZ, 6LG0, 6LG1

  • 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- C -glycosides with different sugar residues. Herein, we report that the biosynthesis of (iso)schaftosides is sequentially catalyzed by two C -glycosyltransferases (CGTs), i.e., CGTa for C -glucosylation of the 2-hydroxyflavanone aglycone and CGTb for C -arabinosylation of the mono- C -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 Scutellaria baicalensis , Glycyrrhiza uralensis , Oryza sativa ssp. japonica , and Zea mays , 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.

  • Organizational Affiliation

    State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191 Beijing, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F
460Scutellaria baicalensisMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.00 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.244 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 97.318α = 90
b = 171.593β = 90
c = 179.169γ = 90
Software Package:
Software NamePurpose
HKL-2000data scaling
PDB_EXTRACTdata extraction
DENZOdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2020-11-18
    Type: Initial release
  • Version 1.1: 2020-12-02
    Changes: Database references
  • Version 1.2: 2020-12-16
    Changes: Database references
  • Version 1.3: 2023-11-22
    Changes: Data collection, Database references, Refinement description