12-oxophytodienoate reductase

 

12-Oxophytodienoate reductase 3 (OPR3) from tomato catalyses the reduction of a carbon-carbon double bond in 9S, 13S-12-oxo-phytodienoate (9S, 13S-OPDA) producing 1S,2S-3-oxo-2(2'[Z]-pentenyl)-cyclopentane-1-octanoate. The product is subsequently converted to jasmonic acid which is a plant hormone. OPR3 is a homologue of old yellow enzyme (OYE) and has a similar catalytic mechanism. OPR3 dimerises with a low affinity in vitro but the dimer is not catalytically active. Dimerisation in vivo could be regulated by phosphorylation as part of a control mechanism..

 

Reference Protein and Structure

Sequence
Q9FEW9 UniProt (1.3.1.42) IPR001155 (Sequence Homologues) (PDB Homologues)
Biological species
Solanum lycopersicum (tomato) Uniprot
PDB
2hsa - Crystal structure of 12-oxophytodienoate reductase 3 (OPR3) from tomato (1.5 Å) PDBe PDBsum 2hsa
Catalytic CATH Domains
3.20.20.70 CATHdb (see all for 2hsa)
Cofactors
Fmnh2(2-) (1)
Click To Show Structure

Enzyme Reaction (EC:1.3.1.42)

8-[(1R,2R)-3-oxo-2-{(Z)-pent-2-en-1-yl}cyclopentyl]octanoate
CHEBI:15720ChEBI
+
NADP(3-)
CHEBI:58349ChEBI
→
(15Z)-12-oxophyto-10,15-dienoate
CHEBI:57411ChEBI
+
NADPH(4-)
CHEBI:57783ChEBI
+
hydron
CHEBI:15378ChEBI
Alternative enzyme names: 12-oxo-phytodienoic acid reductase,

Enzyme Mechanism

Introduction

The reaction proceeds via a ping-pong bi-bi mechanism. NAD(P)H reduces FMN by transfering a hydride ion to N(5) before the substrate binds. FMNH- subsequently transfers the hydride ion to C(beta) of the substrate. Tyr190 protonates C(alpha) of the substrate.

Catalytic Residues Roles

UniProt PDB* (2hsa)
His188 His188(194)A His188, thogether with His185, activates the C(alpha)-C(beta) double bond of the substrate by forming strong hydrogen bonds with the carbonyl oxygen of the substrate. electrostatic stabiliser
His185 His185(191)A His185, thogether with His188, activates the C(alpha)-C(beta) double bond of the substrate by forming strong hydrogen bonds with the carbonyl oxygen of the substrate. electrostatic stabiliser
Tyr190 Tyr190(196)A Tyr190 protonates C(alpha) of the substrate after or during the hydride transfer to C(beta). proton shuttle (general acid/base)
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file; y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain; C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.

Chemical Components

References

  1. Breithaupt C et al. (2006), Proc Natl Acad Sci U S A, 103, 14337-14342. Crystal structure of 12-oxophytodienoate reductase 3 from tomato: Self-inhibition by dimerization. DOI:10.1073/pnas.0606603103. PMID:16983071.

Step 1.

Download: Image, Marvin File

Catalytic Residues Roles

Residue Roles
His185(191)A electrostatic stabiliser
Tyr190(196)A proton shuttle (general acid/base)
His188(194)A electrostatic stabiliser

Chemical Components

Step 1.

Contributors

Gemma L. Holliday