Production of Coenzyme $Q_{10}$ by Recombinant E. coli Harboring the Decaprenyl Diphosphate Synthase Gene from Sinorhizobium meliloti

Decaprenyl diphosphate synthase (DPS) is the key enzyme for the production of coenzyme Q 10 (CoQ 10 ). A dps gene from Sinorhizobium meliloti KCCM 11232 (IFO 14782) was isolated by PCR and then cloned in Escherichia coli. DNA sequencing analysis revealed an open reading frame of 1,017 bp encoding a 338-amino-acid protein. The protein was identical at the 98% level to the putative octaprenyl diphosphate synthase (IspB) of S. meliloti 1021. The deduced amino acid sequence included the DDxxD domains conserved in the majority of the prenyl diphosphate synthases. Heterologous expression in E. coli BL21(DE3) was carried out, and the CoQ 10 produced was then analyzed by HPLC. E. coli BL21(DE3) harboring the dps gene from S. meliloti produced CoQ 10 in addition to endogenous coenzyme Q 8 (CoQ 8 ), whereas wild-type E. coli BL21(DE3) host did not have the ability of producing CoQ 10 . The results suggest that the putative dps from S. meliloti KCTC 2353 encoded the DPS.