Figure 4. Model of catalysis.

a) Model of phenazine prenylation based on crystal structures, in silico docking and site-directed mutagenesis. The reactions centers of DMAPP (blue) and dhPCA (purple) are emphasized with spheres. Water molecule W1 (magenta) deprotonates the intermediate Wheland complex. EpzP mutants that confirm the model of catalysis or have been engineered to modify turnover-rates are colored orange and green, respectively. 1,6-dihydroxy naphthalene (green), the substrate of NphB, occupies essentially the same binding pocket as dhPCA in EpzP. b) Schematic view of substrate binding in EpzP. c) and d) Relative enzymatic activities of EpzP variants compared to the wild-type EpzP.