8W71

Structural basis of chorismate isomerization by Arabidopsis isochorismate synthase ICS1

8W71 の概要

• エントリーDOI: 10.2210/pdb8w71/pdb
• 分子名称: Isochorismate synthase 1, chloroplastic, (3R,4R)-3-[(1-carboxyethenyl)oxy]-4-hydroxycyclohexa-1,5-diene-1-carboxylic acid, MAGNESIUM ION, ... (5 entities in total)
• 機能のキーワード: chorismate-bound atics1 complex, isomerase
• 由来する生物種: Arabidopsis thaliana (thale cress)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 119044.53

構造登録者

Su, Z.H.,Ming, Z.H. (登録日: 2023-08-30, 公開日: 2024-05-22, 最終更新日: 2024-10-16)

主引用文献

Su, Z.,Niu, C.,Zhou, S.,Xu, G.,Zhu, P.,Fu, Q.,Zhang, Y.,Ming, Z.
Structural basis of chorismate isomerization by Arabidopsis ISOCHORISMATE SYNTHASE1.
Plant Physiol., 196:773-787, 2024

PubMed Abstract: Salicylic acid (SA) plays a crucial role in plant defense against biotrophic and semibiotrophic pathogens. In Arabidopsis (Arabidopsis thaliana), isochorismate synthase 1 (AtICS1) is a key enzyme for the pathogen-induced biosynthesis of SA via catalytic conversion of chorismate into isochorismate, an essential precursor for SA synthesis. Despite the extensive knowledge of ICS1-related menaquinone, siderophore, and tryptophan (MST) enzymes in bacteria, the structural mechanisms for substrate binding and catalysis in plant isochorismate synthase (ICS) enzymes are unknown. This study reveals that plant ICS enzymes catalyze the isomerization of chorismate through a magnesium-dependent mechanism, with AtICS1 exhibiting the most substantial catalytic activity. Additionally, we present high-resolution crystal structures of apo AtICS1 and its complex with chorismate, offering detailed insights into the mechanisms of substrate recognition and catalysis. Importantly, our investigation indicates the existence of a potential substrate entrance channel and a gating mechanism regulating substrate into the catalytic site. Structural comparisons of AtICS1 with MST enzymes suggest a shared structural framework with conserved gating and catalytic mechanisms. This work provides valuable insights into the structural and regulatory mechanisms governing substrate delivery and catalysis in AtICS1, as well as other plant ICS enzymes.

PubMed: 38701037
DOI: 10.1093/plphys/kiae260

実験手法

X-RAY DIFFRACTION (2.121 Å)