Cis-2', 3'-dihydrodiol production on flavone B-ring by biphenyl dioxygenase from Pseudomonas pseudoalcaligenes KF707 expressed in Escherichia coli.
Escherichia coli JM109 strains expressing either toluene dioxygenase from Pseudomonas putida F1 or biphenyl dioxygenase from Pseudomonas pseudoalcaligenes KF707 were examined for their ability to catalyze flavones. Biphenyl dioxygenase produced metabolites from flavone and 5,7-dihydroxyflavone which were not found in the control experiments. The absorption maxima of UV-visible spectra for the metabolites from flavone and 5,7-dihydroxyflavone were found at 337 and 348 nm respectively by using a photodiode array detector in the HPLC. Liquid chromatography/mass spectroscopy (LC/MS) showed molecular weights 256 and 288 for the metabolites, respectively. The metabolite of flavone, which was isolated and purified from the bacterial culture, was further subjected to analysis by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Based on the LC/MS and NMR results, biphenyl dioxygenase inserted oxygen at C2' and C3' on the B-ring of flavone, resulting in the formation of flavone cis-2', 3'-dihydrodiol (2-[3,4-dihydroxy-1.5-cyclohexadienyl]-4H-chromen-4-one). Since this product is not found in Chemical Abstracts, this compound is considered a novel one. In addition, biotransformation of flavones by biphenyl dioxygenase suggested a potential role of bacterial dioxygenase to synthesize novel compounds from plant secondary metabolites.
Kim
Song-Young
SY
School of Agricultural Biotechnology, Seoul National University, Suwon 441-744, Korea.
Jung
Jihyun
J
Lim
Yoongho
Y
Ahn
Joong-Hoon
JH
Kim
Su-Il
SI
Hur
Hor-Gil
HG
D001426:Bacterial Proteins / Q000235:genetics; D001711:Biotransformation; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism*; D015870:Gene Expression; D010105:Oxygenases / Q000235:genetics* / Q000378:metabolism*; D044205:Pseudomonas pseudoalcaligenes / Q000201:enzymology* / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D005419:Flavonoids; D011994:Recombinant Proteins; C043561:chrysin; D010105:Oxygenases; C023172:toluene dioxygenase