title: Identification and heterologous expression of a Δ4-fatty acid desaturase gene from Isochrysis sphaerica.
abstract: The marine microalga Isochrysis sphaerica is rich in the very-long-chain polyunsaturated fatty acids, including eicosapentaenoic acid (EPA, C20:5ω-3) and docosahexaenoic acid (DHA, C22:6ω-3) that are important to human health. Here, we report a functional characterization of a Δ4-fatty acid desaturase gene (FAD4) from I. sphaerica. IsFAD4 contains a 1,284 bp open reading frame encoding a 427 amino acid polypeptide. The deduced amino sequence comprises three conserved histidine motifs and a cytochrome b5 domain at its N-terminus. Phylogenetic analysis indicated that IsFad4 formed a unique Isochrysis clade distinct from the counterparts of other eukaryotes. Heterologous expression of IsFAD4 in Pichia pastoris showed that IsFad4 was able to desaturate docosapentaenoic acid (DPA) to form DHA, and the rate of converting DPA to DHA was 79.8%. These results throw light on the potential industrial production of specific polyunsaturated fatty acids through IsFAD4 transgenic yeast or oil crops.
authors.affiliation: Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Guo
authors.forename: Mulan
authors.initials: M
authors.lastname: Jiang
authors.forename: Xia
authors.initials: X
authors.lastname: Wan
authors.forename: Yangmin
authors.initials: Y
authors.lastname: Gong
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Liang
authors.forename: Chuanjiong
authors.initials: C
authors.lastname: Hu
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D016000:Cluster Analysis; D048028:DNA, Algal / Q000737:chemistry / Q000235:genetics; D004281:Docosahexaenoic Acids / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D015870:Gene Expression; D058087:Haptophyta / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D048028:DNA, Algal; D005231:Fatty Acids, Unsaturated; D011994:Recombinant Proteins; D004281:Docosahexaenoic Acids; D044943:Fatty Acid Desaturases; C434953:delta-4 fatty acid desaturase; C026219:docosapentaenoic acid