Structural biology study of isoflavonoid phytoalexin biosynthesis
Isoflavonoids are very valuable secondary metabolites primarily produced in leguminous plants. They have significant health benefits for humans. As phytoalexins, they play important roles in plant defense against microorganisms. Medicarpin, the major isoflavonoid phytoalexin in alfalfa responding to fungal pathogen attack, is synthesized via the isoflavonoid branch of phenylpropanoid metabolism. There are several enzymes involved in this biosynthetic process. To improve our understanding of this biosynthetic pathway in detail, we are investigating the three dimensional structures of these enzymes, the interactions with their substrates/co-factors, and their catalytic mechanisms.
Publications:
Wang, X., He, X., Lin, J., Shao, H., Chang, Z., Dixon, R.A. (2006). Crystal structure of isoflavone reductase from Alfalfa (Medicago sativa L.). J. Mol. Biol. 358, 1341-1352.
Shao, H., Dixon, R.A., Wang, X. (2007). Crystal structure of vestitone reductase from Alfalfa (Medicago sativa L.). J. Mol. Biol. 369, 265-276.
Click to Enlarge Figures
From left: Figure 1. Phenylpropanoid pathway and biosynthesis of isoflavonoid phytoalexin medicarpin; Figure 2. Ribbon diagram of the IFR structure; and Figure 3. The putative binding pocket for co-factor and substrate. NADPH and 2'-hydroxyformononetin were docked into the proposed binding pockets.
