A new prokaryotic farnesyldiphosphate synthase from the octocoral Eunicea fusca: differential display, inverse PCR, cloning, and characterization.

We recently reported that the biosynthesis of fuscol, a diterpene from the octocoral Eunicea fusca, is inducible by the application of plant signaling factors such as salicylic acid to the coral's algal symbiont. In this study, an mRNA differential display approach has been employed with the dinoflagellate symbiont of this octocoral which has led to the isolation of a farnesyldiphosphate synthase (FPPS) that was transcriptionally activated under conditions that led to an induction of fuscol biosynthesis. Using a degenerate primer based on the aspartate-rich motifs found in prenylsynthases and a cassette ligation strategy, we report the cloning of the complete FPPS associated with the E. fusca dinoflagellate symbiont Symbiodinium sp. The protein exhibited the enzymatic properties associated with FPPS, namely, the synthesis of farnesyl diphosphate from geranyldiphosphate and isopentenyl diphosphate. The amino acid sequence of this FPPS has a high sequence similarity (82%) to known archaeal isoprenyl diphosphate synthases. This is the first description of a prokaryotic FPPS derived from a marine source.