8HOK image
Entry Detail
PDB ID:
8HOK
Keywords:
Title:
crystal structure of UGT71AP2
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2022-12-10
Release Date:
2023-12-13
Method Details:
Experimental Method:
Resolution:
2.15 Å
R-Value Free:
0.21
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
I 2 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:UGT71AP2
Chain IDs:A
Chain Length:464
Number of Molecules:1
Biological Source:Scutellaria baicalensis
Primary Citation
Functional characterization, structural basis, and protein engineering of a rare flavonoid 2'- O -glycosyltransferase from Scutellaria baicalensis .
Acta Pharm Sin B 14 3746 3759 (2024)
PMID: 39220864 DOI: 10.1016/j.apsb.2024.04.001

Abstact

Glycosylation is an important post-modification reaction in plant secondary metabolism, and contributes to structural diversity of bioactive natural products. In plants, glycosylation is usually catalyzed by UDP-glycosyltransferases. Flavonoid 2'-O-glycosides are rare glycosides. However, no UGTs have been reported, thus far, to specifically catalyze 2'-O-glycosylation of flavonoids. In this work, UGT71AP2 was identified from the medicinal plant Scutellaria baicalensis as the first flavonoid 2'-O-glycosyltransferase. It could preferentially transfer a glycosyl moiety to 2'-hydroxy of at least nine flavonoids to yield six new compounds. Some of the 2'-O-glycosides showed noticeable inhibitory activities against cyclooxygenase 2. The crystal structure of UGT71AP2 (2.15 Å) was solved, and mechanisms of its regio-selectivity was interpreted by pK a calculations, molecular docking, MD simulation, MM/GBSA binding free energy, QM/MM, and hydrogen‒deuterium exchange mass spectrometry analysis. Through structure-guided rational design, we obtained the L138T/V179D/M180T mutant with remarkably enhanced regio-selectivity (the ratio of 7-O-glycosylation byproducts decreased from 48% to 4%) and catalytic efficiency of 2'-O-glycosylation (k cat/K m, 0.23 L/(s·μmol), 12-fold higher than the native). Moreover, UGT71AP2 also possesses moderate UDP-dependent de-glycosylation activity, and is a dual function glycosyltransferase. This work provides an efficient biocatalyst and sets a good example for protein engineering to optimize enzyme catalytic features through rational design.

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