Poster: Metabolic engineering

Abs # 301: Mutation of ζ-carotene-producing phytoene desaturase to produce phytofluene

Presenter:	Zhang, Hong , zhhong@nfri.affrc.go.jp
Authors	Zhang, Hong  (A)   Nagao, Akihiko  (A)
Affiliations:	(A): National Food Research Institue

Recent studies suggest that phytofluene and ζ-carotene besides lycopene are also responsible for the biological activities of tomatoes. Breeding of phytofluene and ζ-carotene in Escherichia coli is expected due to their little accumulations in plants. Although phytoene desaturase (Pds) from plants can convert phytoene to ζ-carotene via phytofluene, it was reported that only ζ-carotene without phytofluene accumulation, was exclusive end product when the gene encoding plant type Pds was expressed in E. coli. In order to enable biosynthesis of phytofluene in E. coli, we carried out DNA shuffling of phytoene desaturase gene from Arabidopsis thaliana. As a result, four phytofluene-producing mutants were isolated and then sequenced. We also used site-mutagenesis to investigate the effect of each mutated amino acids on product specificity. This is the first example to engineer the phytoene desaturase, ζ-carotene-producing enzyme, to produce phytofluene.