Identification of protein-protein interactions of isoflavonoid biosynthetic enzymes with 2-hydroxyisoflavanone synthase in soybean (Glycine max (L.) Merr.)

Toshiyuki Waki, Dong Chan Yoo, Naoto Fujino, Ryo Mameda, Konstantin Denessiouk, Satoshi Yamashita, Reiko Motohashi, Tomoyoshi Akashi, Toshio Aoki, Shin Ichi Ayabe, Seiji Takahashi, Toru Nakayama

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Metabolic enzymes, including those involved in flavonoid biosynthesis, are proposed to form weakly bound, ordered protein complexes, called "metabolons". Some hypothetical models of flavonoid biosynthetic metabolons have been proposed, in which metabolic enzymes are believed to anchor to the cytoplasmic surface of the endoplasmic reticulum (ER) via ER-bound cytochrome P450 isozymes (P450s). However, no convincing evidence for the interaction of flavonoid biosynthetic enzymes with P450s has been reported previously. Here, we analyzed binary protein-protein interactions of 2-hydroxyisoflavanone synthase 1 (GmIFS1), a P450 (CYP93C), with cytoplasmic enzymes involved in isoflavone biosynthesis in soybean. We identified binary interactions between GmIFS1 and chalcone synthase 1 (GmCHS1) and between GmIFS1 and chalcone isomerases (GmCHIs) by using a split-ubiquitin membrane yeast two-hybrid system. These binary interactions were confirmed in planta by means of bimolecular fluorescence complementation (BiFC) using tobacco leaf cells. In these BiFC analyses, fluorescence signals that arose from the interaction of these cytoplasmic enzymes with GmIFS1 generated sharp, network-like intracellular patterns, which was very similar to the ER-localized fluorescence patterns of GmIFS1 labeled with a fluorescent protein. These observations provide strong evidence that, in planta, interaction of GmCHS1 and GmCHIs with GmIFS1 takes place on ER on which GmIFS1 is located, and also provide important clues to understand how enzymes and proteins form metabolons to establish efficient metabolic flux of (iso)flavonoid biosynthesis.

Original languageEnglish
Pages (from-to)546-551
Number of pages6
JournalBiochemical and biophysical research communications
Issue number3
Publication statusPublished - 2016 Jan 15


  • 2-Hydroxyisoflavanone synthase
  • Chalcone isomerase
  • Chalcone synthase
  • Isoflavone
  • Metabolon
  • Protein-protein interaction

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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