3ea4

Arabidopsis thaliana acetohydroxyacid synthase in complex with monosulfuron-ester

spinqualitylabelsall models 3ea4, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ea4 is a 1 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 2.8Å Ligands: 2SM, CSD, FAB, MG, NHE, TDM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ILVB_ARATH Catalyzes the formation of acetolactate from pyruvate, the first step in valine and isoleucine biosynthesis. [:] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Acetohydroxyacid synthase (AHAS; EC 2.2.1.6) is the first enzyme in the biosynthetic pathway of the branched-chain amino acids. It catalyzes the conversion of two molecules of pyruvate into 2-acetolactate or one molecule of pyruvate and one molecule of 2-ketobutyrate into 2-aceto-2-hydroxybutyrate. AHAS requires the cofactors thiamine diphosphate (ThDP), Mg(2+) and FAD for activity. The herbicides that target this enzyme are effective in protecting a broad range of crops from weed species. However, resistance in the field is now a serious problem worldwide. To address this, two new sulfonylureas, monosulfuron and monosulfuron ester, have been developed as commercial herbicides in China. These molecules differ from the traditional sulfonylureas in that the heterocyclic ring attached to the nitrogen atom of the sulfonylurea bridge is monosubstituted rather than disubstituted. The structures of these compounds in complex with the catalytic subunit of Arabidopsis thaliana AHAS have been determined to 3.0 and 2.8 A, respectively. In both complexes, these molecules are bound in the tunnel leading to the active site, such that the sole substituent of the heterocyclic ring is buried deepest and oriented towards the ThDP. Unlike the structures of Arabidopsis thaliana AHAS in complex with the classic disubstituted sulfonylureas, where ThDP is broken, this cofactor is intact and present most likely as the hydroxylethyl intermediate. Crystal structures of two novel sulfonylurea herbicides in complex with Arabidopsis thaliana acetohydroxyacid synthase.,Wang JG, Lee PK, Dong YH, Pang SS, Duggleby RG, Li ZM, Guddat LW FEBS J. 2009 Mar;276(5):1282-90. PMID:19187232 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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