8ET5

Crystal structure of arabidopsis thaliana acetohydroxyacid synthase S653T mutant in complex with amidosulfuron

Summary for 8ET5

• Entry DOI: 10.2210/pdb8et5/pdb
• Related: 5K2O
• Descriptor: Acetolactate synthase, chloroplastic, MAGNESIUM ION, FLAVIN-ADENINE DINUCLEOTIDE, ... (9 entities in total)
• Functional Keywords: herbicide, resistance, ahas, als, ligase, transferase
• Biological source: Arabidopsis thaliana (thale cress)
• Total number of polymer chains: 1
• Total formula weight: 67076.52

Authors

Guddat, L.W.,Cheng, Y. (deposition date: 2022-10-16, release date: 2023-03-29, Last modification date: 2024-11-13)

Primary citation

Cheng, Y.,Lonhienne, T.,Garcia, M.D.,Williams, C.M.,Schenk, G.,Guddat, L.W.
Crystal Structure of the Commercial Herbicide, Amidosulfuron, in Complex with Arabidopsis thaliana Acetohydroxyacid Synthase.
J.Agric.Food Chem., 71:5117-5126, 2023

PubMed Abstract: Amidosulfuron (AS) is from the commercial sulfonylurea herbicide family. It is highly effective against dicot broad-leaf weeds. This herbicide targets acetohydroxyacid synthase (AHAS), the first enzyme in the branched chain amino acid biosynthesis pathway. Here, we have determined the crystal structure of AS in complex with wildtype AHAS (AHAS) and with the resistance mutant, S653T. In both structures, the cofactor, ThDP, is modified to a peracetate adduct, consistent with time-dependent accumulative inhibition. Compared to other AHAS-inhibiting herbicides of the sulfonylurea family, AS lacks a second aromatic ring. The replacement is an aryl sulfonyl group with a reduced number of interactions with the enzyme and relatively low affinity ( = 4.2 μM vs low nM when two heteroaromatic rings are present). This study shows that effective herbicides can have a relatively high for plant AHAS but can still be a potent herbicide provided accumulative inhibition also occurs.

PubMed: 36943718
DOI: 10.1021/acs.jafc.2c08528

Experimental method

X-RAY DIFFRACTION (2.94 Å)