Absolute configuration-dependent epoxide formation from isoflavan-4-ol stereoisomers by biphenyl dioxygenase of Pseudomonas pseudoalcaligenes strain KF707.
Biphenyl dioxygenase from Pseudomonas pseudoalcaligenes strain KF707 expressed in Escherichia coli was found to exhibit monooxygenase activity toward four stereoisomers of isoflavan-4-ol. LC-MS and LC-NMR analyses of the metabolites revealed that the corresponding epoxides formed between C2' and C3' on the B-ring of each isoflavan-4-ol substrate were the sole products. The relative reactivity of the stereoisomers was found to be in the order: (3S,4S)-cis-isoflavan-4-ol > (3R,4S)-trans-isoflavan-4-ol > (3S,4R)-trans-isoflavan-4-ol > (3R,4R)-cis-isoflavan-4-ol and this likely depended upon the absolute configuration of the 4-OH group on the isoflavanols, as explained by an enzyme-substrate docking study. The epoxides produced from isoflavan-4-ols by P. pseudoalcaligenes strain KF707 were further abiotically transformed into pterocarpan, the molecular structure of which is commonly found as part of plant-protective phytoalexins, such as maackiain from Cicer arietinum and medicarpin from Medicago sativa.
School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea.
Jiyoung
J
Seo
Su-Il
SI
Kang
Dongho
D
Won
Mihyang
M
Kim
Ji-Young
JY
Ryu
Suk-Woo
SW
Kang
Byung-Hun
BH
Um
Cheol-Ho
CH
Pan
Joong-Hoon
JH
Ahn
Youhoon
Y
Chong
Robert A
RA
Kanaly
Jaehong
J
Han
Hor-Gil
HG
Hur
D002853:Chromatography, Liquid; D003001:Cloning, Molecular; D049308:Dioxygenases / Q000235:genetics / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D007529:Isoflavones / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D044205:Pseudomonas pseudoalcaligenes / Q000201:enzymology*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013237:Stereoisomerism
D004852:Epoxy Compounds; D007529:Isoflavones; D011994:Recombinant Proteins; D049308:Dioxygenases