Figure 4.

Substrate cyclization mechanism analysis of TAS1 KS. A, mutant activity analysis. Cell-free synthesized TAS1 C-A-PCP domain and purified KS domain protein were used for analysis. In vitro reaction conditions are described in “Experimental procedures.” All samples were assayed in triplicate and averaged with S.D. ND, not detected. B, in silico docking simulation using TAS1 KS as a receptor and N-acetoacetyl-l-Ile as a ligand covalently bound onto residue Cys-179. C, proposed model for substrate cyclization.