Abstract
Background: The Delta(6)-desaturase gene, encoding a key enzyme in the biosynthesis of polyunsaturated fatty acids, has potential in pharmaceutical and nutraceutical applications. Results: The Delta(6)-desaturase gene has been isolated from a selected strain of Oomycetes, Pythium sp. BCC53698. The cloned gene (PyDes6) contained an open reading frame (ORF) of 1401 bp encoding 466 amino acid residues. The deduced amino acid sequence shared a high similarity to those of other Delta(6)-desaturases that contained the signature features of a membrane-bound Delta(6)-desaturase, including a cytochrome b(5) and three histidine-rich motifs and membrane-spanning regions. Heterologous expression in Saccharomyces cerevisiae showed that monoene, diene and triene fatty acids having Delta(9)-double bond were substrates for PyDes6. No distinct preference between the n-3 and n-6 polyunsaturated fatty acyl substrates was found. The Delta(6)-desaturated products were markedly increased by codon optimization of PyDes6. Conclusion: The codon-optimized Delta(6)-desaturase gene generated in this study is a promising tool for further reconstitution of the fatty acid profile, in a host system of choice, for the production of economically important fatty acids, particularly the n-3 and n-6 polyunsaturated fatty acids.
