7WAS

SbSOMT in complex with pterostilbene and nicotinamide adenine dinucleotide(NAD+)

Summary for 7WAS

• Entry DOI: 10.2210/pdb7was/pdb
• Related: 7VB8 7WAQ 7WAR
• Descriptor: stilbene O-methyltransferase, Pterostilbene, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, ... (8 entities in total)
• Functional Keywords: pterostilbene, complex, o-methyltransferase, substrate, transferase
• Biological source: Sorghum bicolor (sorghum)
• Total number of polymer chains: 2
• Total formula weight: 85991.58

Authors

Pow, K.C.,Hao, Q. (deposition date: 2021-12-14, release date: 2022-12-21, Last modification date: 2023-11-29)

Primary citation

Lui, A.C.W.,Pow, K.C.,Lin, N.,Lam, L.P.Y.,Liu, G.,Godwin, I.D.,Fan, Z.,Khoo, C.J.,Tobimatsu, Y.,Wang, L.,Hao, Q.,Lo, C.
Regioselective stilbene O-methylations in Saccharinae grasses.
Nat Commun, 14:3462-3462, 2023

PubMed Abstract: O-Methylated stilbenes are prominent nutraceuticals but rarely produced by crops. Here, the inherent ability of two Saccharinae grasses to produce regioselectively O-methylated stilbenes is reported. A stilbene O-methyltransferase, SbSOMT, is first shown to be indispensable for pathogen-inducible pterostilbene (3,5-bis-O-methylated) biosynthesis in sorghum (Sorghum bicolor). Phylogenetic analysis indicates the recruitment of genus-specific SOMTs from canonical caffeic acid O-methyltransferases (COMTs) after the divergence of Sorghum spp. from Saccharum spp. In recombinant enzyme assays, SbSOMT and COMTs regioselectively catalyze O-methylation of stilbene A-ring and B-ring respectively. Subsequently, SOMT-stilbene crystal structures are presented. Whilst SbSOMT shows global structural resemblance to SbCOMT, molecular characterizations illustrate two hydrophobic residues (Ile144/Phe337) crucial for substrate binding orientation leading to 3,5-bis-O-methylations in the A-ring. In contrast, the equivalent residues (Asn128/Asn323) in SbCOMT facilitate an opposite orientation that favors 3'-O-methylation in the B-ring. Consistently, a highly-conserved COMT is likely involved in isorhapontigenin (3'-O-methylated) formation in wounded wild sugarcane (Saccharum spontaneum). Altogether, our work reveals the potential of Saccharinae grasses as a source of O-methylated stilbenes, and rationalize the regioselectivity of SOMT activities for bioengineering of O-methylated stilbenes.

PubMed: 37308495
DOI: 10.1038/s41467-023-38908-5

Experimental method

X-RAY DIFFRACTION (2.401 Å)