2hs6
Crystal structure of the E291K mutant of 12-oxophytodienoate reductase 3 (OPR3) from tomatoCrystal structure of the E291K mutant of 12-oxophytodienoate reductase 3 (OPR3) from tomato
Structural highlights
Function[OPR3_SOLLC] Specifically cleaves olefinic bonds in cyclic enones. Involved in the biosynthesis of jasmonic acid (JA) and perhaps in biosynthesis or metabolism of other oxylipin signaling moleclules. It is required for the spatial and temporal regulation of JA levels during dehiscence of anthers, promoting the stomium degeneration program (By similarity). In vitro, reduces 9S,13S-12-oxophytodienoic acid (9S,13S-OPDA) and 9R,13R-OPDA to 9S,13S-OPC-8:0 and 9R,13R-OPC-8:0, respectively. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed12-Oxophytodienoate reductase (OPR) 3, a homologue of old yellow enzyme (OYE), catalyzes the reduction of 9S,13S-12-oxophytodienoate to the corresponding cyclopentanone, which is subsequently converted to the plant hormone jasmonic acid (JA). JA and JA derivatives, as well as 12-oxophytodienoate and related cyclopentenones, are known to regulate gene expression in plant development and defense. Together with other oxygenated fatty acid derivatives, they form the oxylipin signature in plants, which resembles the pool of prostaglandins in animals. Here, we report the crystal structure of OPR3 from tomato and of two OPR3 mutants. Although the catalytic residues of OPR3 and related OYEs are highly conserved, several characteristic differences can be discerned in the substrate-binding regions, explaining the remarkable substrate stereoselectivity of OPR isozymes. Interestingly, OPR3 crystallized as an extraordinary self-inhibited dimer. Mutagenesis studies and biochemical analysis confirmed a weak dimerization of OPR3 in vitro, which correlated with a loss of enzymatic activity. Based on structural data of OPR3, a putative mechanism for a strong and reversible dimerization of OPR3 in vivo that involves phosphorylation of OPR3 is suggested. This mechanism could contribute to the shaping of the oxylipin signature, which is critical for fine-tuning gene expression in plants. Crystal structure of 12-oxophytodienoate reductase 3 from tomato: self-inhibition by dimerization.,Breithaupt C, Kurzbauer R, Lilie H, Schaller A, Strassner J, Huber R, Macheroux P, Clausen T Proc Natl Acad Sci U S A. 2006 Sep 26;103(39):14337-42. Epub 2006 Sep 18. PMID:16983071[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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