Crystal structure of Arabidopsis thaliana 12-oxophytodienoate reductase isoform 3 in complex with 8-iso prostaglandin A(1).

12-Oxophytodienoate reductase 3 (OPR3), one of the enzymes involved in the biosynthesis of the plant hormone jasmonic acid (JA), catalyzes the reduction of the cyclopentenone ring of (9,13)-12-oxophytodienoate [(9,13)-OPDA]. However, there has been no structural information about the interaction between OPRs and the physiologically relevant (9,13)-OPDA. Here we report the crystal structure of OPR3 in complex with 8- prostaglandin A1 (8- PGA) which has the same stereochemistry in the cyclopentenone ring as in the physiologically relevant 9,13-OPDA. This structure reveals a new binding mode for substrate that likely contributes to the relaxed stereospecificity observed for AtOPR3.