Cloning and functional characterization of a fatty acid Δ6-desaturase from Oenothera biennis: Production of γ-linolenic acid by heterologous expression in Saccharomyces cerevisiae.

Evening primrose Oenothera biennis is grown commercially for γ-linolenic acid (GLA) production by the fatty acid Δ6-desaturase enzymatic reaction. Based on available sequence information, the O. biennis fatty acid Δ6-desaturase gene was cloned, using rapid amplification of cDNA ends methods and reverse transcription-polymerase chain reaction. The deduced amino acid sequence showed high similarity to the plant Δ6-desaturases, which comprised the characteristics of membrane-bound desaturases, including three conserved histidine-rich motifs, hydropathy profile, and a cytochrome b5 domain at the N-terminus. Heterologous expression of the coding sequence in Saccharomyces cerevisiae resulted in the synthesis and accumulation of GLA when provided with linoleic acid substrate. [ABSTRACT FROM AUTHOR]