1T9C
Crystal Structure Of Yeast Acetohydroxyacid Synthase In Complex With A Sulfonylurea Herbicide, Sulfometuron methyl
Summary for 1T9C
| Entry DOI | 10.2210/pdb1t9c/pdb |
| Related | 1N0H 1T9A 1T9B 1T9D |
| Descriptor | Acetolactate synthase, mitochondrial, POTASSIUM ION, MAGNESIUM ION, ... (8 entities in total) |
| Functional Keywords | acetohydroxyacid synthase, acetolactate synthase, herbicide, sulfonylurea, thiamin diphosphate, fad, inhibitor, sulfometuron methyl, transferase |
| Biological source | Saccharomyces cerevisiae (baker's yeast) |
| Cellular location | Mitochondrion: P07342 |
| Total number of polymer chains | 2 |
| Total formula weight | 150048.05 |
| Authors | McCourt, J.A.,Pang, S.S.,Guddat, L.W.,Duggleby, R.G. (deposition date: 2004-05-16, release date: 2004-12-21, Last modification date: 2023-08-23) |
| Primary citation | 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 Cited by 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: 15709745DOI: 10.1021/bi047980a PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.34 Å) |
Structure validation
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