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Type 1 diacylglycerol acyltransferases of Brassica napus preferentially incorporate oleic acid into triacylglycerol.

Aznar-Moreno J, Denolf P, Van Audenhove K, De Bodt S, Engelen S, Fahy D, Wallis JG, Browse J - J. Exp. Bot. (2015)

Bottom Line: Thorough understanding of the enzymology of oil accumulation is critical to the goal of modifying oilseeds for improved vegetable oil production.This strong sensitivity of the BnDGAT1 isozymes to the relative concentrations of acyl-CoA substrates substantially explains the observed fatty acid composition of B. napus seed oil.Understanding these enzymes that are critical for triacylglycerol synthesis will facilitate genetic and biotechnological manipulations to improve this oilseed crop.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.

No MeSH data available.


Related in: MedlinePlus

TAG synthesis by mutant yeast cultures expressing BnDGAT1 enzymes. Yeast were cultured either without fatty acid (No FA), or supplemented with palmitic acid (Palmitate) or with oleic acid (Oleate) to a 500 µM final concentration. Incubation was for 24h at 30°C. (A) Fatty acid composition of isolated TAG under each culture condition; results are means, n=3. (B) Total TAG produced by BnDGAT1 enzymes; results are means ±SD, n=3.
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Figure 8: TAG synthesis by mutant yeast cultures expressing BnDGAT1 enzymes. Yeast were cultured either without fatty acid (No FA), or supplemented with palmitic acid (Palmitate) or with oleic acid (Oleate) to a 500 µM final concentration. Incubation was for 24h at 30°C. (A) Fatty acid composition of isolated TAG under each culture condition; results are means, n=3. (B) Total TAG produced by BnDGAT1 enzymes; results are means ±SD, n=3.

Mentions: Properties of the BnDGAT1 enzymes in vivo were further examined by measuring TAG synthesis of H2146 yeast expressing the enzymes, first without added fatty acid in the medium, then by adding separately either palmitic or oleic acid. Since yeast take up these fatty acids from the medium by esterification to CoA (Faergeman et al., 2001), the supplements provide excess acyl-CoA substrate to the expressed BnDGAT1 enzymes in vivo. After two days’ growth the total TAG accumulated was measured and the fatty acid composition of the TAG analysed. Total 16-carbon fatty acids are the sum of 16:0 (either the product of yeast fatty acid synthase or taken up from the media) and 16:1, the result of 16:0 desaturation by the yeast OLE1p ∆9 desaturase. The 18-carbon fatty acids are 18:0, synthesized by the yeast, and 18:1, whether taken up from the media or the product of 18:0 desaturation by OLE1p. In the absence of any fatty acid supplement, the fractions of fatty acid incorporated by each BnDGAT1 isoform were quite similar, with an average of 45% 16-carbon fatty acids (Fig. 8A). In cultures supplemented with palmitic acid, the proportion of 16-carbon fatty acids increased to ∼51% of total TAG; most of the increase came as 16:1, and the BnDGAT1-1 isozyme incorporated a higher proportion of 16:0+16:1 than the other BnDGAT1 forms. In contrast, oleic acid supplementation reduced 16-carbon fatty acids in TAG to <30% of the total, and 18:1 made up ∼60% of the total TAG fatty acids in yeast supplemented with oleate (Fig. 8A).


Type 1 diacylglycerol acyltransferases of Brassica napus preferentially incorporate oleic acid into triacylglycerol.

Aznar-Moreno J, Denolf P, Van Audenhove K, De Bodt S, Engelen S, Fahy D, Wallis JG, Browse J - J. Exp. Bot. (2015)

TAG synthesis by mutant yeast cultures expressing BnDGAT1 enzymes. Yeast were cultured either without fatty acid (No FA), or supplemented with palmitic acid (Palmitate) or with oleic acid (Oleate) to a 500 µM final concentration. Incubation was for 24h at 30°C. (A) Fatty acid composition of isolated TAG under each culture condition; results are means, n=3. (B) Total TAG produced by BnDGAT1 enzymes; results are means ±SD, n=3.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4588894&req=5

Figure 8: TAG synthesis by mutant yeast cultures expressing BnDGAT1 enzymes. Yeast were cultured either without fatty acid (No FA), or supplemented with palmitic acid (Palmitate) or with oleic acid (Oleate) to a 500 µM final concentration. Incubation was for 24h at 30°C. (A) Fatty acid composition of isolated TAG under each culture condition; results are means, n=3. (B) Total TAG produced by BnDGAT1 enzymes; results are means ±SD, n=3.
Mentions: Properties of the BnDGAT1 enzymes in vivo were further examined by measuring TAG synthesis of H2146 yeast expressing the enzymes, first without added fatty acid in the medium, then by adding separately either palmitic or oleic acid. Since yeast take up these fatty acids from the medium by esterification to CoA (Faergeman et al., 2001), the supplements provide excess acyl-CoA substrate to the expressed BnDGAT1 enzymes in vivo. After two days’ growth the total TAG accumulated was measured and the fatty acid composition of the TAG analysed. Total 16-carbon fatty acids are the sum of 16:0 (either the product of yeast fatty acid synthase or taken up from the media) and 16:1, the result of 16:0 desaturation by the yeast OLE1p ∆9 desaturase. The 18-carbon fatty acids are 18:0, synthesized by the yeast, and 18:1, whether taken up from the media or the product of 18:0 desaturation by OLE1p. In the absence of any fatty acid supplement, the fractions of fatty acid incorporated by each BnDGAT1 isoform were quite similar, with an average of 45% 16-carbon fatty acids (Fig. 8A). In cultures supplemented with palmitic acid, the proportion of 16-carbon fatty acids increased to ∼51% of total TAG; most of the increase came as 16:1, and the BnDGAT1-1 isozyme incorporated a higher proportion of 16:0+16:1 than the other BnDGAT1 forms. In contrast, oleic acid supplementation reduced 16-carbon fatty acids in TAG to <30% of the total, and 18:1 made up ∼60% of the total TAG fatty acids in yeast supplemented with oleate (Fig. 8A).

Bottom Line: Thorough understanding of the enzymology of oil accumulation is critical to the goal of modifying oilseeds for improved vegetable oil production.This strong sensitivity of the BnDGAT1 isozymes to the relative concentrations of acyl-CoA substrates substantially explains the observed fatty acid composition of B. napus seed oil.Understanding these enzymes that are critical for triacylglycerol synthesis will facilitate genetic and biotechnological manipulations to improve this oilseed crop.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.

No MeSH data available.


Related in: MedlinePlus