title: Inhibition of Coenzyme Qs Accumulation in Engineered Escherichia coli by High Concentration of Farnesyl Diphosphate.
abstract: BACKGROUND
  Coenzyme Q 10 (CoQ 10 ) is an isoprenoid component used widely in nutraceutical industries. Farnesyl diphosphate synthase (FPPS) is a responsible enzyme for biosynthesis of farnesyl diphosphate (FPP), a key precursor for CoQs production. This research involved investigating the effect of FPPS over-expression on CoQs production in engineered CoQ 10 -producing Escherichia coli (E. coli).
  
  
  METHODS
  Two CoQ 10 -producing strains, as referred to E. coli Ba and E. coli Br, were transformed by the encoding gene for FPPS (ispA) under the control of either the trc or P BAD promoters.
  
  
  RESULTS
  Over-expression of ispA under the control of P BAD promoter led to a relative increase in CoQ 10 production only in recombinant E. coli Br although induction by arabinose resulted in partial reduction of CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains. Over-expression of ispA under the control of stronger trc promoter, however, led to a severe decrease in CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains, as reflected by reductions from 629±40 to 30±13 and 564±28 to 80±14 μg/g Dried Cell Weight (DCW), respectively. The results showed high level of FPP reduces endogenous CoQ 8 production as well and that CoQs are produced in a complimentary manner, as the increase in production of one decreases the production of the other.
  
  
  CONCLUSIONS
  The reduction in CoQ 10 production can be a result of Dds inhibition by high FPP concentration. Therefore, more effort is needed to verify the role of intermediate metabolite concentration and to optimize production of CoQ 10 .
authors: Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
authors: Mojtaba
authors: M
authors: Samoudi
authors: Department of Biology, Payame-Noor University, Tehran, Iran.
authors: Negar
authors: N
authors: Omid Yeganeh
authors: Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
authors: Hossein
authors: H
authors: Shahbani Zahiri
authors: Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
authors: Parvin
authors: P
authors: Shariati
authors: Department of Biology, Payame-Noor University, Tehran, Iran.
authors: Reza
authors: R
authors: Hajhosseini
keywords: Coenzyme Q10; Decaprenyl diphosphate synthase; Farnesyl diphosphate; Isoprenoid