1T9C

Crystal Structure Of Yeast Acetohydroxyacid Synthase In Complex With A Sulfonylurea Herbicide, Sulfometuron methyl

1T9C の概要

• エントリーDOI: 10.2210/pdb1t9c/pdb
• 関連するPDBエントリー: 1N0H 1T9A 1T9B 1T9D
• 分子名称: Acetolactate synthase, mitochondrial, POTASSIUM ION, MAGNESIUM ION, ... (8 entities in total)
• 機能のキーワード: acetohydroxyacid synthase, acetolactate synthase, herbicide, sulfonylurea, thiamin diphosphate, fad, inhibitor, sulfometuron methyl, transferase
• 由来する生物種: Saccharomyces cerevisiae (baker's yeast)
• 細胞内の位置: Mitochondrion: P07342
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 150048.05

構造登録者

McCourt, J.A.,Pang, S.S.,Guddat, L.W.,Duggleby, R.G. (登録日: 2004-05-16, 公開日: 2004-12-21, 最終更新日: 2023-08-23)

主引用文献

McCourt, J.A.,Pang, S.S.,Guddat, L.W.,Duggleby, R.G.
Elucidating the specificity of binding of sulfonylurea herbicides to acetohydroxyacid synthase.
Biochemistry, 44:2330-2338, 2005

PubMed Abstract: Acetohydroxyacid synthase (AHAS, EC 2.2.1.6) is the target for the sulfonylurea herbicides, which act as potent inhibitors of the enzyme. Chlorsulfuron (marketed as Glean) and sulfometuron methyl (marketed as Oust) are two commercially important members of this family of herbicides. Here we report crystal structures of yeast AHAS in complex with chlorsulfuron (at a resolution of 2.19 A), sulfometuron methyl (2.34 A), and two other sulfonylureas, metsulfuron methyl (2.29 A) and tribenuron methyl (2.58 A). The structures observed suggest why these inhibitors have different potencies and provide clues about the differential effects of mutations in the active site tunnel on various inhibitors. In all of the structures, the thiamin diphosphate cofactor is fragmented, possibly as the result of inhibitor binding. In addition to thiamin diphosphate, AHAS requires FAD for activity. Recently, it has been reported that reduction of FAD can occur as a minor side reaction due to reaction with the carbanion/enamine of the hydroxyethyl-ThDP intermediate that is formed midway through the catalytic cycle. Here we report that the isoalloxazine ring has a bent conformation that would account for its ability to accept electrons from the hydroxyethyl intermediate. Most sequence and mutation data suggest that yeast AHAS is a high-quality model for the plant enzyme.

PubMed: 15709745
DOI: 10.1021/bi047980a

実験手法

X-RAY DIFFRACTION (2.34 Å)