5J33

Isopropylmalate dehydrogenase in complex with NAD+

5J33 の概要

• エントリーDOI: 10.2210/pdb5j33/pdb
• 関連するPDBエントリー: 5J32 5J34
• 分子名称: 3-isopropylmalate dehydrogenase 2, chloroplastic, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, SULFATE ION, ... (4 entities in total)
• 機能のキーワード: dehydrogenase, leucine biosynthesis, glucosinolate biosynthesis, oxidoreductase
• 由来する生物種: Arabidopsis thaliana (Mouse-ear cress)
• 細胞内の位置: Plastid, chloroplast : P93832
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 353803.51

構造登録者

Jez, J.M.,Lee, S.G. (登録日: 2016-03-30, 公開日: 2016-05-18, 最終更新日: 2024-10-23)

主引用文献

Lee, S.G.,Nwumeh, R.,Jez, J.M.
Structure and Mechanism of Isopropylmalate Dehydrogenase from Arabidopsis thaliana: INSIGHTS ON LEUCINE AND ALIPHATIC GLUCOSINOLATE BIOSYNTHESIS.
J.Biol.Chem., 291:13421-13430, 2016

PubMed Abstract: Isopropylmalate dehydrogenase (IPMDH) and 3-(2'-methylthio)ethylmalate dehydrogenase catalyze the oxidative decarboxylation of different β-hydroxyacids in the leucine- and methionine-derived glucosinolate biosynthesis pathways, respectively, in plants. Evolution of the glucosinolate biosynthetic enzyme from IPMDH results from a single amino acid substitution that alters substrate specificity. Here, we present the x-ray crystal structures of Arabidopsis thaliana IPMDH2 (AtIPMDH2) in complex with either isopropylmalate and Mg(2+) or NAD(+) These structures reveal conformational changes that occur upon ligand binding and provide insight on the active site of the enzyme. The x-ray structures and kinetic analysis of site-directed mutants are consistent with a chemical mechanism in which Lys-232 activates a water molecule for catalysis. Structural analysis of the AtIPMDH2 K232M mutant and isothermal titration calorimetry supports a key role of Lys-232 in the reaction mechanism. This study suggests that IPMDH-like enzymes in both leucine and glucosinolate biosynthesis pathways use a common mechanism and that members of the β-hydroxyacid reductive decarboxylase family employ different active site features for similar reactions.

PubMed: 27137927
DOI: 10.1074/jbc.M116.730358

実験手法

X-RAY DIFFRACTION (3.492 Å)