| Structural highlights
7u1d 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 3.11Å |
| Ligands: | CIE, CSD, F50, FAD, MG, NHE, SO4, TP9 |
| 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]
Publication Abstract from PubMed
Acetohydroxyacid synthase (AHAS) is the target for more than 50 commercial herbicides; first applied to crops in the 1980s. Since then, 197 site-of-action resistance isolates have been identified in weeds, with mutations at P197 and W574 the most prevalent. Consequently, AHAS is at risk of not being a useful target for crop protection. To develop new herbicides, a functional understanding to explain the effect these mutations have on activity is required. Here, we show that these mutations can have two effects (i) to reduce binding affinity of the herbicides and (ii) to abolish time-dependent accumulative inhibition, critical to the exceptional effectiveness of this class of herbicide. In the two mutants, conformational changes occur resulting in a loss of accumulative inhibition by most herbicides. However, bispyribac, a bulky herbicide is able to counteract the detrimental effects of these mutations, explaining why no site-of-action resistance has yet been reported for this herbicide.
Structural basis of resistance to herbicides that target acetohydroxyacid synthase.,Lonhienne T, Cheng Y, Garcia MD, Hu SH, Low YS, Schenk G, Williams CM, Guddat LW Nat Commun. 2022 Jun 11;13(1):3368. doi: 10.1038/s41467-022-31023-x. PMID:35690625[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:https://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
- ↑ Lonhienne T, Cheng Y, Garcia MD, Hu SH, Low YS, Schenk G, Williams CM, Guddat LW. Structural basis of resistance to herbicides that target acetohydroxyacid synthase. Nat Commun. 2022 Jun 11;13(1):3368. doi: 10.1038/s41467-022-31023-x. PMID:35690625 doi:https://dx.doi.org/10.1038/s41467-022-31023-x
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