6KVL

Crystal structure of UDP-RebB-SrUGT76G1

Summary for 6KVL

• Entry DOI: 10.2210/pdb6kvl/pdb
• Descriptor: UDP-glycosyltransferase 76G1, URIDINE-5'-DIPHOSPHATE, (8alpha,9beta,10alpha,13alpha)-13-{[beta-D-glucopyranosyl-(1->2)-[beta-D-glucopyranosyl-(1->3)]-beta-D-glucopyranosyl]oxy}kaur-16-en-18-oic acid, ... (4 entities in total)
• Functional Keywords: glycosyltransferase, diterpenoid, stevia rebaudiana, natural sweeteners, steviol glycosides (sgs)., transferase
• Biological source: Stevia rebaudiana (Stevia)
• Total number of polymer chains: 1
• Total formula weight: 53615.49

Authors

Li, J.X.,Liu, Z.F.,Wang, Y.,Zhang, P. (deposition date: 2019-09-04, release date: 2019-11-20, Last modification date: 2023-11-22)

Primary citation

Liu, Z.,Li, J.,Sun, Y.,Zhang, P.,Wang, Y.
Structural Insights into the Catalytic Mechanism of a Plant Diterpene Glycosyltransferase SrUGT76G1.
Plant Commun., 1:100004-100004, 2020

PubMed Abstract: Diterpene glycosyltransferase UGT76G1 from (SrUGT76G1) is key to the generation of economically important steviol glycosides (SGs), a group of natural sweeteners with high-intensity sweetness. SrUGT76G1 accommodates a wide range of steviol-derived substrates and many other small molecules. We report here the crystal structures of SrUGT76G1 in complex with multiple ligands to answer how this enzyme recognizes diterpenoid aglycones and catalyzes the 1,3-sugar chain branching. A spacious pocket for sugar-acceptor binding was observed from the determined SrUGT76G1 structures, which can explain its broad substrate spectrum. Residues Gly87 and Leu204 lining the pocket play key roles in switching between diterpenoid and flavonoid glucosylation. An engineered mutant of SrUGT76G1, T284S, could catalyze a selectively increased production of next-generation sweetener rebaudioside M, with diminished side product of rebaudioside I. Taken together, these resutls provide significant insights into molecular basis of the substrate specificity of scarcely documented diterpenoid glycosyltransferases and would facilitate the structure-guided glycoengineering to produce diversified diterpenoids with new activities.

PubMed: 33404544
DOI: 10.1016/j.xplc.2019.100004

Experimental method

X-RAY DIFFRACTION (1.998 Å)