The codon-optimized ∆ 6 -desaturase gene of Pythium sp. as an empowering tool for engineering n3/n6 polyunsaturated fatty acid biosynthesis

Abstract

Background: The {increment}6-desaturase gene, encoding a key enzyme in the biosynthesis of polyunsaturated fatty acids, has potential in pharmaceutical and nutraceutical applications. Results: The {increment}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 1401bp encoding 466 amino acid residues. The deduced amino acid sequence shared a high similarity to those of other {increment}6-desaturases that contained the signature features of a membrane-bound {increment}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 {increment}9-double bond were substrates for PyDes6. No distinct preference between the n-3 and n-6 polyunsaturated fatty acyl substrates was found. The {increment}6-desaturated products were markedly increased by codon optimization of PyDes6. Conclusion: The codon-optimized {increment}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.