Comparison of the Substrate Preferences of ω3 Fatty Acid Desaturases for Long Chain Polyunsaturated Fatty Acids

Abstract

Omega-3 long chain polyunsaturated fatty acids (ω3 LC-PUFAs) such as eicosapentaenoic acid (EPA; 20:5ω3) and docosahexaenoic acid (DHA; 22:6ω3) are important fatty acids for human health. These ω3 LC-PUFAs are produced from their ω3 precursors by a set of desaturases and elongases involved in the biosynthesis pathway and are also converted from ω6 LC-PUFA by omega-3 desaturases (ω3Ds). Here, we have investigated eight ω3-desaturases obtained from a cyanobacterium, plants, fungi and a lower animal species for their activities and compared their specificities for various C18, C20 and C22 ω6 PUFA substrates by transiently expressing them in Nicotiana benthamiana leaves. Our results showed hitherto unreported activity of many of the ω3Ds on ω6 LC-PUFA substrates leading to their conversion to ω3 LC-PUFAs. This discovery could be important in the engineering of EPA and DHA in heterologous hosts.

Lipid Distribution Pattern and Transcriptomic Insights Revealed the Potential Mechanism of Docosahexaenoic Acid Traffics in Schizochytrium sp. A-2

“…18 Screening of more specific or more active C22-specific ω-3 desaturase may be needed in the future. 19 In addition, the previous report showed that the supplementation of propionic acid in the medium increased the ratio of DHA/ DPAn6 slightly, but the concentrations of DHA and DPAn6 were all decreased. 20 In contrast to the synchronous increase of DHA and DPAn6, the percentage of EPA decreased in TAG although it increased in TFAs during the growth of the cell (Table 1 and Figure 2B).…”

“…However, overexpression of an ω-3 desaturase from Saprolegnia diclina only slightly increased the conversion of DPAn6 to DHA . Screening of more specific or more active C22-specific ω-3 desaturase may be needed in the future . In addition, the previous report showed that the supplementation of propionic acid in the medium increased the ratio of DHA/DPAn6 slightly, but the concentrations of DHA and DPAn6 were all decreased .…”

Biological Role of Unsaturated Fatty Acid Desaturases in Health and Disease

“…Progress in genetic engineering opened a perspective for modification of fatty acid desaturases to enrich cultivated plants in particularly desirable FAs. Many research groups obtained transgenic plants that can synthesize and accumulate selected FAs, such as OA, EPA, DHA, and SDA [19,[73][74][75][76][77]. For example, expression of borage (Borago officinalis) D6D in oilseed crops contributed to increase in SDA levels up to 20% of all FAs present in these plants [73,74].…”

New Sustainable Oil Seed Sources of Omega-3 Long-Chain Polyunsaturated Fatty Acids: A Journey from the Ocean to the Field

“…Use of a marine microalgae ∆6-desaturase with a higher preference for ω3 substrate than ω6 substrate [38] Pyraminomas cordata ∆6-elongase 18:4ω3 to 20:4ω3 (SDA to ETA) High conversion efficiency of SDA to ETA via ∆6-elongase [39] Pavlova salina ∆5-desaturase 20:4ω3 to 20:5ω3 (ETA to EPA) Demonstrated the acyl-CoA desaturation ability [39,40] Pyraminomas cordata ∆5-elongase 20:5ω3 to 22:5ω3 (EPA to ω3 DPA) Highly efficient ∆5-elongase targeted to maximise the elongation from EPA to ω3 DPA [39] Pavlova salina ∆4-desaturase 22:5ω3 to 22:6ω3 (ω3 DPA to DHA) Demonstrated the acyl-CoA desaturation ability [40] ω3 desaturases from various sources conversion of ω6 PUFA and ω6 LC-PUFA to ω3 PUFA and ω3 LC-PUFA Results in very low amounts of ω6 fatty acids and contributed to the high ω3/ω6 ratio [41] Multiple attempts have been made to achieve the fish oil-like levels of ω3 LC-PUFA for commercialisation. The first consideration was to enhance the fatty acid flux from oleic acid (OA, 18:1ω9) to ω3 ALA by introducing a yeast ∆12-desaturase and ω3-desaturase, in addition to the endogenous ∆12-desaturase and ∆15-desaturase.…”