Literature Information

Title	Production of bioactive hydroxyflavones by using monooxygenase from Saccharothrix espanaensis
Author	Hyejin Lee , Bong-Gyu Kim , Joong-Hoon Ahn
DOI	10.1016/j.jbiotec.2014.02.002
Abstract	Biocatalysts are a valuable tool for the structural modification of fine chemicals. Flavonoids possess several biological activities, which are correlated to their antioxidant activity. The numbers of hydroxyl groups in flavonoids are critical for their antioxidant activity. Development of biocatalysts for hydroxylation of flavonoids is challenging because of the difficulty in expressing flavonoid hydroxylase in Escherichia coli. In this study, a monooxygenase from Saccharothrix espanaensis (Sam5) was used for regioselective hydroxylation of flavonoids. We found that Sam5 hydroxylated isoflavones, flavanones, and flavones but did not produce any detectable hydroxylated product with flavonols. In addition, coexpression of P450 reductase with Sam5 in E. coli enhanced hydroxylation by approximately from 34 to 50%, depending on the flavonoid used. The production of two bioactive flavonoids, 8-hydroxyluteolin and 3’-hydroxydaidzein was optimized using this Sam5 system. Approximately 88mg/L of 8-hydroxyluteolin and 75mg/L of 3’-hydroxydaidzein were obtained. These results indicate that the Sam5 system could be used for the production of bioactive hydroxylated flavonoids.

Experimental results

• Enzyme

Uniprot ID: Q2EYY8

Protein: 4-coumarate 3-hydroxylase

Organism: Saccharothrix espanaensis

Length: 512 AA

Taxonomic identifier: 103731 [NCBI]

• Pfam

Source	Domain	Start	End	E-value (Domain)	Coverage
Pfam-A	HpaB	289	490	2.5e-68	0.990
Pfam-A	HpaB_N	19	283	3e-94	0.996

Program: hmmscan

Version: 3.1b2 (February 2015)

Method: hmmscan --domtblout hmmscan.tbl --noali -E 1e-5 pfam query.fa

Date: Mon Jul 20 14:32:16 2020

Description:

1. HpaB

Pfam

HpaB Q57160 encodes part of the 4-hydroxyphenylacetate 3-hydroxylase from Escherichia coli ¹. HpaB is part of a heterodimeric enzyme that also requires HpaC. The enzyme is NADH-dependent and uses FAD as the redox chromophore. This family also includes PvcC O30372 may play a role in one of the proposed hydroxylation steps of pyoverdine chromophore biosynthesis ².

InterPro

This C-terminal domain is found in HpaB, which encodes part of the 4-hydroxyphenylacetate 3-hydroxylase from Escherichia coli¹. The enzyme is NADH-dependent and uses FAD as the redox chromophore. This domain is also found in pyoverdin chromophore biosynthetic protein PvcC, which may play a role in one of the proposed hydroxylation steps of pyoverdine chromophore biosynthesis² and in 4-hydroxybutyryl-CoA dehydratase (4-BUDH), a key enzyme in the metabolism of gamma-aminobutyrate³.

2. HpaB_N

Pfam

HpaB Q57160 encodes part of the 4-hydroxyphenylacetate 3-hydroxylase from Escherichia coli¹. HpaB is part of a heterodimeric enzyme that also requires HpaC. The enzyme is NADH-dependent and uses FAD as the redox chromophore. This family also includes PvcC O30372 may play a role in one of the proposed hydroxylation steps of pyoverdine chromophore biosynthesis².

InterPro

This domain is found in the N terminus of HpaB, which encodes part of the 4-hydroxyphenylacetate 3-hydroxylase from Escherichia coli¹. The enzyme is NADH-dependent and uses FAD as the redox chromophore. The domain is also found in pyoverdin chromophore biosynthetic protein (PvcC), which may play a role in one of the proposed hydroxylation steps of pyoverdine chromophore biosynthesis² and in 4-hydroxybutyryl-CoA dehydratase (4-BUDH), a key enzyme in the metabolism of gamma-aminobutyrate³.

Information is taken from Pfam and InterPro web site.

• Reaction

luteolin ⇒ 8-hydroxyluteolin

References