Dirigent proteins impart stereoselectivity on the phenoxy radical-coupling reaction, yielding optically active lignans from two molecules of coniferyl alcohol in the biosynthesis of lignans, flavonolignans, and alkaloids and thus plays a central role in plant secondary metabolism. Enantiocomplementary dirigent protein that mediates the laccase-catalyzed enantioselective oxidative phenol coupling of (E)-coniferyl alcohol to (-)-pinoresinol. Homodimer. Expressed in roots, cotyledon veins, leaf trichomes, flowers, siliques, and meristems. Present in interfascicular/vascular cambia and developing xylem. In flowers, expressed in the vasculature of petals, stamen filaments, anther microsporangia, and papillar cells of the stigma and style. In siliques, accumulates in the stigmatic region, replum, funiculus, and valve. Belongs to the plant dirigent protein family.