2R2G

Structure of Eugenol Synthase from Ocimum basilicum complexed with EMDF

2R2G の概要

• エントリーDOI: 10.2210/pdb2r2g/pdb
• 関連するPDBエントリー: 2QW8 2QX7 2QYS 2QZ2 2QZZ
• 分子名称: Eugenol synthase 1, NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, ethyl (1S,2S)-2-(4-hydroxy-3-methoxyphenyl)cyclopropanecarboxylate, ... (4 entities in total)
• 機能のキーワード: eugenol, phenylpropene, pip reductase, short-chain dehydrogenase/reductase, plant protein
• 由来する生物種: Ocimum basilicum (sweet basil)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 73936.17

構造登録者

Louie, G.V.,Noel, J.P.,Bowman, M.E. (登録日: 2007-08-24, 公開日: 2008-01-15, 最終更新日: 2023-08-30)

主引用文献

Louie, G.V.,Baiga, T.J.,Bowman, M.E.,Koeduka, T.,Taylor, J.H.,Spassova, S.M.,Pichersky, E.,Noel, J.P.
Structure and reaction mechanism of basil eugenol synthase
Plos One, 2:e993-e993, 2007

PubMed Abstract: Phenylpropenes, a large group of plant volatile compounds that serve in multiple roles in defense and pollinator attraction, contain a propenyl side chain. Eugenol synthase (EGS) catalyzes the reductive displacement of acetate from the propenyl side chain of the substrate coniferyl acetate to produce the allyl-phenylpropene eugenol. We report here the structure determination of EGS from basil (Ocimum basilicum) by protein x-ray crystallography. EGS is structurally related to the short-chain dehydrogenase/reductases (SDRs), and in particular, enzymes in the isoflavone-reductase-like subfamily. The structure of a ternary complex of EGS bound to the cofactor NADP(H) and a mixed competitive inhibitor EMDF ((7S,8S)-ethyl (7,8-methylene)-dihydroferulate) provides a detailed view of the binding interactions within the EGS active site and a starting point for mutagenic examination of the unusual reductive mechanism of EGS. The key interactions between EMDF and the EGS-holoenzyme include stacking of the phenyl ring of EMDF against the cofactor's nicotinamide ring and a water-mediated hydrogen-bonding interaction between the EMDF 4-hydroxy group and the side-chain amino moiety of a conserved lysine residue, Lys132. The C4 carbon of nicotinamide resides immediately adjacent to the site of hydride addition, the C7 carbon of cinnamyl acetate substrates. The inhibitor-bound EGS structure suggests a two-step reaction mechanism involving the formation of a quinone-methide prior to reduction. The formation of this intermediate is promoted by a hydrogen-bonding network that favors deprotonation of the substrate's 4-hydroxyl group and disfavors binding of the acetate moiety, akin to a push-pull catalytic mechanism. Notably, the catalytic involvement in EGS of the conserved Lys132 in preparing the phenolic substrate for quinone methide formation through the proton-relay network appears to be an adaptation of the analogous role in hydrogen bonding played by the equivalent lysine residue in other enzymes of the SDR family.

PubMed: 17912370
DOI: 10.1371/journal.pone.0000993

実験手法

X-RAY DIFFRACTION (1.8 Å)