| Structural highlights
3e9y 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 3Å |
| Ligands: | , , , , , |
| 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.[1] [2] [:][3] [4] [5] [6] [7] [8]
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[9]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Mazur BJ, Chui CF, Smith JK. Isolation and characterization of plant genes coding for acetolactate synthase, the target enzyme for two classes of herbicides. Plant Physiol. 1987 Dec;85(4):1110-7. PMID:16665813
- ↑ Sathasivan K, Haughn GW, Murai N. Nucleotide sequence of a mutant acetolactate synthase gene from an imidazolinone-resistant Arabidopsis thaliana var. Columbia. Nucleic Acids Res. 1990 Apr 25;18(8):2188. PMID:2336405
- ↑ Haughn GW, Somerville CR. A Mutation Causing Imidazolinone Resistance Maps to the Csr1 Locus of Arabidopsis thaliana. Plant Physiol. 1990 Apr;92(4):1081-5. PMID:16667374
- ↑ Sathasivan K, Haughn GW, Murai N. Molecular Basis of Imidazolinone Herbicide Resistance in Arabidopsis thaliana var Columbia. Plant Physiol. 1991 Nov;97(3):1044-50. PMID:16668488
- ↑ Ott KH, Kwagh JG, Stockton GW, Sidorov V, Kakefuda G. Rational molecular design and genetic engineering of herbicide resistant crops by structure modeling and site-directed mutagenesis of acetohydroxyacid synthase. J Mol Biol. 1996 Oct 25;263(2):359-68. PMID:8913312 doi:http://dx.doi.org/10.1006/jmbi.1996.0580
- ↑ Chang AK, Duggleby RG. Expression, purification and characterization of Arabidopsis thaliana acetohydroxyacid synthase. Biochem J. 1997 Oct 1;327 ( Pt 1):161-9. PMID:9355748
- ↑ Chang AK, Duggleby RG. Herbicide-resistant forms of Arabidopsis thaliana acetohydroxyacid synthase: characterization of the catalytic properties and sensitivity to inhibitors of four defined mutants. Biochem J. 1998 Aug 1;333 ( Pt 3):765-77. PMID:9677339
- ↑ Lee YT, Chang AK, Duggleby RG. Effect of mutagenesis at serine 653 of Arabidopsis thaliana acetohydroxyacid synthase on the sensitivity to imidazolinone and sulfonylurea herbicides. FEBS Lett. 1999 Jun 11;452(3):341-5. PMID:10386618
- ↑ Wang JG, Lee PK, Dong YH, Pang SS, Duggleby RG, Li ZM, Guddat LW. Crystal structures of two novel sulfonylurea herbicides in complex with Arabidopsis thaliana acetohydroxyacid synthase. FEBS J. 2009 Mar;276(5):1282-90. PMID:19187232 doi:http://dx.doi.org/EJB6863
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