Abstract
Prenyltransferases occur widely in prokaryotes and eukaryotes, among which membrane-bound type enzymes are involved in the biosynthesis of various quinines, e.g. plastoquinone and in the formation of prenylated aromatic secondary metabolites like planylated flavonoids in plants. However, due to the difficulty in the biochemical handling almost nothing is known about the enzymatic function of those membrane-bound prenyltransferases. In this study, we used LePGT1, which accepted p-hydroxybenzoic acid (PHB) and geranyl diphosphate (GPP) as substrates, as a model of such membrane-bound prenyltransferases and the crucial amino acids were identified by site-directed mutagenesis. Moreover, we generated the 3D structure of substrate binding pocket by molecular modeling, which provided a reasonable structure to explain the biochemical data obtained by the characterization of mutant enzymes. The domain determining the substrate specificity of LePGT1 to GPP will be also discussed using this model.
