Molecular and biochemical characterization of 2-hydroxyisoflavanone dehydratase. Involvement of carboxylesterase-like proteins in leguminous isoflavone biosynthesis

被引:122
作者
Akashi, T [1 ]
Aoki, T [1 ]
Ayabe, S [1 ]
机构
[1] Nihon Univ, Dept Appl Biol Sci, Fujisawa, Kanagawa 2528510, Japan
关键词
D O I
10.1104/pp.104.056747
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
Isoflavonoids are ecophysiologically active secondary metabolites of the Leguminosae and known for health-promoting phytoestrogenic functions. Isoflavones are synthesized by 1,2-elimination of water from 2-hydroxyisoflavanones, the first intermediate with the isoflavonoid skeleton, but details of this dehydration have been unclear. We screened the extracts of repeatedly fractionated Escherichia coli expressing a Glycyrrhiza echinata cDNA library for the activity to convert a radiolabeled precursor into formononetin (7-hydroxy-4'-methoxyisoflavone), and a clone of 2-hydroxyisoflavanone dehydratase (HID) was isolated. Another HID cDNA was cloned from soybean (Glycine max), based on the sequence information in its expressed sequence tag library. Kinetic studies revealed that G. echinata HID is specific to 2,7-dihydroxy-4'-methoxyisoflavanone, while soybean HID has broader specificity to both 4'-hydroxylated and 4'-methoxylated 2-hydroxyisoflavanones, reflecting the structures of isoflavones contained in each plant species. Strikingly, HID proteins were members of a large carboxylesterase family, of which plant proteins form a monophyletic group and some are assigned defensive functions with no intrinsic catalytic activities identified. Site-directed mutagenesis with soybean HID protein suggested that the characteristic oxyanion hole and catalytic triad are essential for the dehydratase as well as the faint esterase activities. The findings, to our knowledge, represent a new example of recruitment of enzymes of primary metabolism during the molecular evolution of plant secondary metabolism.
引用
收藏
页码:882 / 891
页数:10
相关论文
共 48 条
[1]   New scheme of the biosynthesis of formononetin involving 2,7,4′-trihydroxyisofiavanone but not daidzein as the methyl acceptor [J].
Akashi, T ;
Sawada, Y ;
Aoki, T ;
Ayabe, S .
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 2000, 64 (10) :2276-2279
[2]   Cloning and functional expression of a cytochrome P450 cDNA encoding 2-hydroxyisoflavanone synthase involved in biosynthesis of the isoflavonoid skeleton in licorice [J].
Akashi, T ;
Aoki, T ;
Ayabe, S .
PLANT PHYSIOLOGY, 1999, 121 (03) :821-828
[3]   cDNA cloning and biochemical characterization of S-adenosyl-L-methionine:: 2,7,4′-trihydroxyisoflavanone 4′-O-methyltransferase, a critical enzyme of the legume isoflavonoid phytoalexin pathway [J].
Akashi, T ;
Sawada, Y ;
Shimada, N ;
Sakurai, N ;
Aoki, T ;
Ayabe, S .
PLANT AND CELL PHYSIOLOGY, 2003, 44 (02) :103-112
[4]   Anthocyanin-producing dandelion callus as a chalcone synthase source in recombinant polyketide reductase assay [J].
Akashi, T ;
Saito, N ;
Hirota, H ;
Ayabe, S .
PHYTOCHEMISTRY, 1997, 46 (02) :283-287
[5]   Flavonoids of leguminous plants: Structure, biological activity, and biosynthesis [J].
Aoki, T ;
Akashi, T ;
Ayabe, S .
JOURNAL OF PLANT RESEARCH, 2000, 113 (1112) :475-488
[6]   Generation of 7137 non-redundant expressed sequence tags from a legume, Lotus japonicus [J].
Asamizu, E ;
Nakamura, Y ;
Sato, S ;
Tabata, S .
DNA RESEARCH, 2000, 7 (02) :127-130
[7]  
Ayabe S, 2002, METHOD ENZYMOL, V357, P360
[8]  
BARZ W, 1992, RECENT ADV PHYTOCHEM, V26, P139
[9]   Cloning of a grapevine Botrytis-responsive gene that has homology to the tobacco hypersensitivity-related hsr203J [J].
Bézier, A ;
Lambert, B ;
Baillieul, F .
JOURNAL OF EXPERIMENTAL BOTANY, 2002, 53 (378) :2279-2280
[10]   ROLE OF A BURIED ACID GROUP IN MECHANISM OF ACTION OF CHYMOTRYPSIN [J].
BLOW, DM ;
BIRKTOFT, JJ ;
HARTLEY, BS .
NATURE, 1969, 221 (5178) :337-&