Putative DP active-site pockets.
A, (+)-pinoresinol–forming DP, DRR206. Several residues lining the DRR206 active-site pocket are differentially conserved in (+)- or (–)-pinoresinol–forming DPs, suggesting a role in determining substrate orientation. The Ω loop is labeled to indicate proximity to the backside of the active site. B, PsPTS1, residue numbers differ by one (less) from those in GePTS1. C, modeled GhDIR4.