(+)-Pinoresinol/(+)-lariciresinol reductase from Forsythia intermedia. Protein purification, cDNA cloning, heterologous expression and comparison to isoflavone reductase.
Lignans are a widely distributed class of natural products, whose functions and distribution suggest that they are one of the earliest forms of defense to have evolved in vascular plants; some, such as podophyllotoxin and enterodiol, have important roles in cancer chemotherapy and prevention, respectively. Entry into lignan enzymology has been gained by the approximately 3000-fold purification of two isoforms of (+)-pinoresinol/(+)-lariciresinol reductase, a pivotal branchpoint enzyme in lignan biosynthesis. Both have comparable ( approximately 34.9 kDa) molecular mass and kinetic (Vmax/Km) properties and catalyze sequential, NADPH-dependent, stereospecific, hydride transfers where the incoming hydride takes up the pro-R position. The gene encoding (+)-pinoresinol/(+)-lariciresinol reductase has been cloned and the recombinant protein heterologously expressed as a functional beta-galactosidase fusion protein. Its amino acid sequence reveals a strong homology to isoflavone reductase, a key branchpoint enzyme in isoflavonoid metabolism and primarily found in the Fabaceae (angiosperms). This is of great evolutionary significance since both lignans and isoflavonoids have comparable plant defense properties, as well as similar roles as phytoestrogens. Given that lignans are widespread from primitive plants onwards, whereas the isoflavone reductase-derived isoflavonoids are mainly restricted to the Fabaceae, it is tempting to speculate that this branch of the isoflavonoid pathway arose via evolutionary divergence from that giving the lignans.
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA. lewisn@wsu.edu
A T
AT
Dinkova-Kostova
D R
DR
Gang
L B
LB
Davin
D L
DL
Bedgar
A
A
Chu
N G
NG
Lewis
D000595:Amino Acid Sequence; D001483:Base Sequence; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010088:Oxidoreductases / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010944:Plants / Q000201:enzymology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D010088:Oxidoreductases; C084968:lariciresinol reductase; C084969:pinoresinol reductase; C071072:vestitone reductase; D044925:Oxidoreductases Acting on CH-CH Group Donors