1. Identification of a polyphenol O-methyltransferase with broad substrate flexibility in Streptomyces albidoflavus J1074.
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Pérez-Valero, Álvaro, Magadán-Corpas, Patricia, Dulak, Kinga, Matera, Agata, Ye, Suhui, Huszcza, Ewa, Popłoński, Jarosław, Villar, Claudio J., and Lombó, Felipe
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BIOCHEMICAL substrates , *COMPLEMENTATION (Genetics) , *FLAVONOIDS , *CAFFEIC acid , *FLAVONES - Abstract
Flavonoids are a large and important group of phytochemicals with a great variety of bioactivities. The addition of methyl groups during biosynthesis of flavonoids and other polyphenols enhances their bioactivities and increases their stability. In a previous study of our research group, we detected a novel flavonoid O-methyltransferase activity in Streptomyces albidoflavus J1074, which led to the heterologous biosynthesis of homohesperetin from hesperetin in feeding cultures. In this study, we identify the O-methyltransferase responsible for the generation of this methylated flavonoid through the construction of a knockout mutant of the gene XNR_0417, which was selected after a blast analysis using the sequence of a caffeic acid 3′-O-methyltransferase from Zea mays against the genome of S. albidoflavus J1074. This mutant strain, S. albidoflavus ∆XNR_0417, was no longer able to produce homohesperetin after hesperetin feeding. Subsequently, we carried out a genetic complementation of the mutant strain in order to confirm that the enzyme encoded by XNR_0417 is responsible for the observed O-methyltransferase activity. This new strain, S. albidoflavus SP43-XNR_0417, was able to produce not only homohesperetin from hesperetin, but also different mono-, di-, tri- and tetra-methylated derivatives on other flavanones, flavones and stilbenes, revealing a broad substrate flexibility. Additionally, in vitro experiments were conducted using the purified enzyme on the substrates previously tested in vivo, demonstrating doubtless the capability of XNR_0417 to generate various methylated derivatives. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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