6lsv
From Proteopedia
Crystal structure of JOX2 in complex with 2OG, Fe, and JA
Structural highlights
FunctionJOX2_ARATH 2-oxoglutarate-dependent dioxygenase involved in the oxidation of jasmonate (JA), a stress-induced phytohormone synthesized in response to attack by pathogens and herbivores, which triggers the activation of defense responses via the JA-mediated signaling pathway (PubMed:28760569, PubMed:28559313). Converts JA to 12-hydroxyjasmonate (12OH-JA), an inactive form of JA (PubMed:28760569, PubMed:28559313, PubMed:33516967). Is specific to free JA, and cannot oxidize the bioactive form jasmonoyl-L-isoleucine (JA-Ile) or other JA-amino acid conjugates (PubMed:28760569, PubMed:33516967). Prevents over-accumulation of JA and indirectly its bioactive form JA-Ile under stress response (PubMed:28760569, PubMed:28559313). Acts as negative regulator of JA-mediated defense signaling, by contributing to 12OH-JA accumulation, which represses JA defense responses upon infection by the fungal pathogen Botrytis cinerea (PubMed:28760569, PubMed:28559313). Acts as negative regulator of JA-mediated defense responses upon infestation by the herbivorous caterpillar Mamestra brassicae (PubMed:28559313). May be involved in the catabolism of cytotoxic polycyclic aromatic hydrocarbons (PAHs) (PubMed:27637093).[1] [2] [3] [4] Publication Abstract from PubMedThe jasmonic acid (JA) signaling pathway is used by plants to control wound responses. The persistent accumulation of JA inhibits plant growth, and the hydroxylation of JA to 12-hydroxy-JA by JASMONATE-INDUCED OXYGENASEs (JOXs, also named jasmonic acid oxidases) is therefore vital for plant growth, while structural details of JA recognition by JOXs are unknown. Here, we present the 2.65 A resolution X-ray crystal structure of Arabidopsis JOX2 in complex with its substrate JA and its co-substrates 2-oxoglutarate and Fe(II). JOX2 contains a distorted double-stranded beta helix (DSBH) core flanked by alpha helices and loops. JA is bound in the narrow substrate pocket by hydrogen bonds with the arginine triad R225, R350, and R354 and by hydrophobic interactions mainly with the phenylalanine triad F157, F317, and F346. The most critical residues for JA binding are F157 and R225, both from the DSBH core, which interact with the cyclopentane ring of JA. The spatial distribution of critical residues for JA binding and the shape of the substrate-binding pocket together define the substrate selectivity of the JOXs. Sequence alignment shows that these critical residues are conserved among JOXs from higher plants. Collectively, our study provides insights into the mechanism by which higher plants hydroxylate the hormone JA. Structure-guided analysis of Arabidopsis JASMONATE-INDUCED OXYGENASE (JOX) 2 reveals key residues for recognition of jasmonic acid substrate by plant JOXs.,Zhang X, Wang D, Elberse J, Qi L, Shi W, Peng YL, Schuurink RC, Van den Ackerveken G, Liu J Mol Plant. 2021 May 3;14(5):820-828. doi: 10.1016/j.molp.2021.01.017. Epub 2021, Jan 28. PMID:33516967[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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