Dramatic changes in the substrate specificities of prenyltransferase by a single amino acid substitution

Abstract

Farnesyl diphosphate (FPP) synthase catalyzes the condensation of isopentenyl diphosphate (IPP) with dimethylallyl diphosphate (DMAPP) or geranyl diphosphate (GPP) to give FPP as a final product. The FPP synthase of a thermophilic bacterium, Bacillus stearothermophilus, can hardly accept substrate analogs having oxygen atoms in their prenyl chain though the porcine FPP synthase can accept them.We have prepared several point-mutated B. stearothermophilus FPP synthases, in which tyrosine was substituted with glycine (Y81G), serine (Y81S), arginine (Y81R) or aspartic acid (Y81D). Interestingly, the reactivities of the mutated FPP synthases were enhanced with respect to the substrate analogs having ω-oxygen atom in their prenyl chain (1–4).