Discovery of Potential Acetohydroxyacid Synthase Covalent Inhibitors with Integrated Virtual Screening Approach

Acetohydroxyacid synthase (AHAS) is an important target for over 50 commercial herbicides. However, increasing herbicide resistance in weeds has made control difficult, and developing covalent inhibitors may be an effective strategy. Here, a hybrid virtual screening strategy combining structure-based, ligand-based, and molecular simulation calculations was developed based on covalent binding effects and first employed to discover potential AHAS covalent inhibitors. A refined database of 5178 sulfonyl fluoride-containing small molecules was obtained via pesticide similarity screening. The database was initially screened by noncovalent docking, and higher-scoring compounds were reranked using integrated 2D and 3D similarity search tools to obtain 723 molecules. Two potential covalent inhibitors, Z2768276635 and Z2901771932, were successfully screened by covalent docking and DFT calculations. Notably, Z2768276635 showed excellent inhibitory activity against AtAHAS with a Ki value of 0.12 μM, superior to bispyribac (0.44 μM). This work offers a meaningful starting point for developing covalent inhibitor pesticides.