6lbp | pdb_00006lbp
Structure of the Glutamine Phosphoribosylpyrophosphate Amidotransferase from Arabidopsis thaliana
Structural highlights
FunctionASE2_ARATH Catalyzes the first committed step of 'de novo purine biosynthesis from glutamine. Required for chloroplast biogenesis and cell division. Confers sensitivity to the phenyltriazole acetic acid compound [5-(4-chlorophenyl)-1-isopropyl-1H-[1,2,4]triazol-3-yl]-acetic acid (DAS734), a bleaching herbicide.[1] [2] [3] Publication Abstract from PubMedChloroplastic glutamine phosphoribosylpyrophosphate amidotransferase (GPRATase) catalyzes the first committed step of de novo purine biosynthesis in Arabidopsis thaliana, and DAS734 is a direct and specific inhibitor of AtGPRAT, with phytotoxic effects similar to the leaf beaching phenotypes of known AtGPRAT genetic mutants, especially cia1 and atd2. However, the structure of AtGPRAT and the inhibition mode of DAS734 still remain poorly understood. In this study, we solved the structure of AtGPRAT2, which revealed structural differences between AtGPRAT2 and bacterial enzymes. Kinetics assay demonstrated that DAS734 behaves as a competitive inhibitor for the substrate phosphoribosyl pyrophosphate (PRPP) of AtGPRAT2. Docking studies showed that DAS734 forms electrostatic interactions with R264 and hydrophobic interactions with several residues, which was verified by binding assays. Collectively, our study provides important insights into the inhibition mechanism of DAS734 to AtGPRAT2 and sheds light on future studies into further development of more potent herbicides targeting Arabidopsis GPRATases. Crystal Structure of the Chloroplastic Glutamine Phosphoribosylpyrophosphate Amidotransferase GPRAT2 From Arabidopsis thaliana.,Cao X, Du B, Han F, Zhou Y, Ren J, Wang W, Chen Z, Zhang Y Front Plant Sci. 2020 Feb 27;11:157. doi: 10.3389/fpls.2020.00157. eCollection, 2020. PMID:32174940[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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