Fig. 1: The location of the herbicide resistance sites in Arabidopsis thaliana AHAS (AtAHAS).

a Stereoview of AtAHAS (PDB code: 5K6Q³⁰) with pyruvate (Pyr_1 and Pyr_2) and an intact ThDP cofactor modeled. This model is based on the structure of the highly homologous Saccharomyces cerevisiae AHAS (ScAHAS), whose structure has been solved in complex with pyruvate (PDB code: 6BD9³⁷). The first pyruvate interacts with W574 through an anion–π interaction. The second pyruvate makes contact with P197. Residues that confer resistance (in yellow) upon herbicide selection pressure are found in the substrate access channel. b Stereoview of the AtAHAS-penoxsulam structure (PDB code: 5WJ1,¹¹) showing the positions of the residues involved in resistance relative to the herbicide, penoxsulam (PS, in cyan). “ThAthDP” and “Per” indicate thiamine thiazolone diphosphate (an oxidized product of ThDP) and peracetate, respectively.