Identification and characterization of a novel enzyme related to the synthesis of PUFAs derived from thraustochytrium aureum ATCC 34304

Abstract

In Thraustochytrids, Thraustochytrium aureum ATCC 34304 was able to produce high levels of several polyunsaturated fatty acids. In the present study, a novel gene encoding protein was cloned from the DHA rich microbe, T. aureum ATCC 34304. The functional analysis of a novel gene was demonstrated by its heterologous expression in Pichia pastoris. The gene was able to synthesize C20 and C22 PUFAs, as well as, to mediate different elongations (Δ9, Δ6, and Δ5) and one Δ5 desaturation activities. The conversion rates of the Δ9 elongation (n-3) and Δ5 desaturation products were found to be higher in response to the novel enzyme than the controls (TaElo and Tad5, respectively). The other Δ9 elongation (n-6) and Δ5 elongation products were slightly lower than those of the control (TaElo). The full length of the 1,374 bp gene contained 458 amino acids that showed very limited homology with desaturases and elongases from various organisms. In addition, the rate of synthesis of PUFAs was evaluated at temperatures ranging from 10 to 30°C. The elongation products were found to decrease dramatically and the desaturation products were found to increase dramatically at 10°C. TaNE was confirmed to be a multifunctional enzyme with higher activity towards Δ6 elongations than Δ9, Δ5 elongations, and Δ5 desaturation.