Figure 7. Structural representation of the ThDP-binding site.

The active site centred at ThDP was modelled by a SwissProt database program using the X-ray co-ordinates of yeast AHAS (Protein Data Bank code 1N0H). The three-dimensional structure represented here was constructed with the inhibitor, chlorimuron ethyl. Trp⁵⁸⁶′ was shown only when inhibitor was added to the crystal formation. Trp⁵⁰³′ and Trp⁵⁸⁶′ correspond to residues Trp⁴⁹⁰ and Trp⁵⁷³ of tobacco AHAS respectively. Protein side chains close to ThDP or within 5 Å to the likely position of active sites are shown, with residues from the domain of one subunit designated as a number and those from the other subunit as a primed number.