8w71 | pdb_00008w71

Structural basis of chorismate isomerization by Arabidopsis isochorismate synthase ICS1

spinqualitylabelsall models 8w71, resolution 2.12Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8w71 is a 2 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.121Å Ligands: FMT, ISJ, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ICS1_ARATH Isochorismate synthase involved in the synthesis of salicylic acid (SA) required for both local and systemic acquired resistance (LAR and SAR) while SA synthesized through the phenylalanine ammonium lyase (PAL) pathway seems to potentiate plant cell death. Also involved in phylloquinone (vitamin K1) synthesis. Has no isochorismate pyruvate lyase (IPL) activity. Publication Abstract from PubMed Salicylic acid (SA) plays a crucial role in plant defense against biotrophic and semi-biotrophic 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, 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. Structural basis of chorismate isomerization by Arabidopsis ISOCHORISMATE SYNTHASE1.,Su Z, Niu C, Zhou S, Xu G, Zhu P, Fu Q, Zhang Y, Ming Z Plant Physiol. 2024 May 3:kiae260. doi: 10.1093/plphys/kiae260. PMID:38701037 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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