The recombinant delta-4 Fatty Acid Desaturases from Thraustochytrium aureum ATCC 26185 and BK1, Involved in the Biosynthesis of Docosahexanoic Acid Heterologous Expression in E. coli and Yeast

초록

Thraustochytrium is a unicellular marine eukaryotic microoganism and unusually produces long chain polyunsaturated fatty acids such as DHA and docosapentanoic acid (DPA) 22:5(n-6). DHA(docosahexanoic acid) is a fatty acid of the (n-3) series, according to the location of the last double bond at the methyl end. The Fad4 and putative Tad4, coding for delta4 fatty acid desaturases from Thraustochytrium aureum ATCC 26185 and BK1, respectively were amplified by PCR and cloned into pMAL portein expression vector. The function of Fad4 and putative Tad4 was identified as the enzyme which involved in the biosynthesis of docosahexanoic acid(DHA) by fatty acid profiles. In the present study, when the Fad4 or putative Tad4 from Thraustochytrium aureum was expressed in E. coli and yeast at the lower temperature, the fatty acid composition was changed, resulting in the production of DHA and other long-chain unsaturated fatty acids. There results would be the valuable raw data for large scale DHA production and ongoing investigations of DHA synthetic pathway in lower enkaryotes.