D4 desaturases and D5 elongases
Disclosed are methods and compositions related to ONC-T18, D4-desaturases, D5 elongases, their isolation, characterization, production, identification, and use for fatty acid production, as well as organisms containing these compositions and organisms expressing them.
1. A composition comprising an isolated D4 desaturase, wherein the D4 desaturase has at least 98% sequence identity to SEQ ID NO:26 and wherein the desaturase activity is retained.
2. The composition of claim 1 , wherein the isolated D4 desaturase has conservative changes.
3. A composition comprising an isolated nucleic acid, wherein the nucleic acid encodes the D4 desaturase of claim 1 .
4. The composition of claim 3 , further comprising a vector.
5. An isolated cell, wherein the cell comprises the composition of claim 1 .
6. The cell of claim 5 , wherein the cell is a plant or non-human animal cell.
7. The cell of claim 5 , wherein the cell is a Thraustochytrid , a yeast, or an Escherichia coli.
8. The composition of claim 1 , wherein the composition produces more polyunsaturated fatty acids than the composition in the absence of the D4 desaturase.
9. The composition of claim 8 , wherein the fatty acid is Eicosapentaenoic acid (EPA) or Docosahexaenoic acid (DHA).
10. The composition of claim 1 , wherein the desaturase contains at least one histidine box.
11. The composition of claim 10 , wherein the histidine box comprises the sequence HXXHH (SEQ ID NO:27), wherein X is any amino acid.
12. The composition of claim 10 , wherein the histidine box comprises SEQ ID NO:28.
13. The composition of claim 10 , wherein the desaturase also comprises a cytochrome b5 domain.
14. The composition of claim 13 , wherein the cytochrome b5 domain resides at the N-terminal end.
15. A method for producing a polyunsaturated fatty acid comprising: culturing a cell comprising an isolated D4 desaturase in a suitable nutrient medium, wherein the D4 desaturase has at least 98% sequence identity to SEQ ID NO:26.
16. The method of claim 15 , wherein the fatty acid produced is ARA, EPA or DHA.