# Promiscuous Transferases Malonylate Furaneol Glucoside in Fragaria × ananassa

## TL;DR

Strawberries use enzymes called FaMATs to modify Furaneol glucoside, creating stable compounds that could be useful for drug development.

## Contribution

Discovery of promiscuous malonyltransferases in strawberries that modify glycosides with broad substrate tolerance.

## Key findings

- FaMAT1C, FaMAT1S, and FaMAT4C1/S1 catalyze malonylation of HDMF glucoside, producing three isomers.
- FaMATs successfully malonylated 67 structurally diverse glycosides.
- Malonylation at the glucose 6-OH position prevents glycosidic bond cleavage, stabilizing glycosides.

## Abstract

Acylation is essential in plant metabolism, protecting
metabolites
from enzymatic degradation, aiding xenobiotic detoxification, and
regulating cellular uptake. It also enhances the stability, solubility,
and bioactivity of natural products, making it valuable for drug discovery.
Since HDMF (4-hydroxy-2,5-dimethyl-3­(2H)-furanone;
Furaneol) 6′-O-malonyl glucoside was detected
in strawberries, we hypothesized that strawberry malonyltransferases
(FaMATs) acylate HDMF glucoside. Genome analysis of Fragaria × ananassa and biochemical assays identified
FaMAT1C, FaMAT1S, and FaMAT4C1/S1 as enzymes
catalyzing its malonylation, producing three isomerslikely
due to keto–enol tautomerism. A screening revealed the broad
substrate tolerance of FaMATs, with successful malonylation observed
in 67 structurally different glycosides. Notably, FaMAT4C1/S1 malonylated maple furanone glucoside at the 6-OH position
of the glucose moiety resulted in previously unknown metabolites.
This modification stabilizes glycosides by preventing glycosidic bond
cleavage by glycosidases. Understanding FaMAT function deepens insights
into plant specialized metabolism and supports the development of
natural product-based therapeutics.