TY - JOUR
T1 - Cloning and functional characterisation of a fatty acyl elongase from southern bluefin tuna (Thunnus maccoyii).
AU - Gregory, Melissa
AU - See, Valene
AU - Gibson, Robert
AU - Schuller, Kathryn
PY - 2010/2
Y1 - 2010/2
N2 - The synthesis of long chain polyunsaturated fatty acids (LCPUFA), such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), involves fatty acyl desaturase and elongase enzymes. The marine fish species southern bluefin tuna (SBT) can accumulate large quantities of omega-3 (n-3) LCPUFA in its flesh but their capacity to synthesize EPA and DHA is uncertain. A cDNA, sbtElovl5, encoding a putative fatty acyl elongase was amplified from SBT liver tissue. The cDNA included an open reading frame (ORF) encoding 294 amino acids. Sequence comparisons and phylogenetic analyses revealed a high level of sequence conservation between sbtElovl5 and fatty acyl elongase sequences from other fish species. Heterologous expression of the sbtElovl5 ORF in Saccharomyces cerevisiae confirmed that it encoded a fatty acyl elongase capable of elongating C18/20 polyunsaturated fatty acid (PUFA) substrates, but not C22 PUFA substrates. For the first time in an Elovl5, the substrate competition occurring in nature was investigated. Higher activity towards n-3 PUFA substrates than omega-6 (n-6) PUFA substrates was exhibited, regardless of substrate chain length. The sbtElovl5 preferentially elongated 18:4n-3 and 18:3n-6 rather than 20:5n-3 and 20:4n-6. The sbtElovl5 enzyme also elongated saturated and monounsaturated fatty acids. Crown
AB - The synthesis of long chain polyunsaturated fatty acids (LCPUFA), such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), involves fatty acyl desaturase and elongase enzymes. The marine fish species southern bluefin tuna (SBT) can accumulate large quantities of omega-3 (n-3) LCPUFA in its flesh but their capacity to synthesize EPA and DHA is uncertain. A cDNA, sbtElovl5, encoding a putative fatty acyl elongase was amplified from SBT liver tissue. The cDNA included an open reading frame (ORF) encoding 294 amino acids. Sequence comparisons and phylogenetic analyses revealed a high level of sequence conservation between sbtElovl5 and fatty acyl elongase sequences from other fish species. Heterologous expression of the sbtElovl5 ORF in Saccharomyces cerevisiae confirmed that it encoded a fatty acyl elongase capable of elongating C18/20 polyunsaturated fatty acid (PUFA) substrates, but not C22 PUFA substrates. For the first time in an Elovl5, the substrate competition occurring in nature was investigated. Higher activity towards n-3 PUFA substrates than omega-6 (n-6) PUFA substrates was exhibited, regardless of substrate chain length. The sbtElovl5 preferentially elongated 18:4n-3 and 18:3n-6 rather than 20:5n-3 and 20:4n-6. The sbtElovl5 enzyme also elongated saturated and monounsaturated fatty acids. Crown
KW - Aquaculture
KW - cDNA
KW - Fatty acyl elongase
KW - Long chain polyunsaturated fatty acids
KW - Southern bluefin tuna
KW - Yeast expression
UR - http://www.scopus.com/inward/record.url?scp=71849091908&partnerID=8YFLogxK
U2 - 10.1016/j.cbpb.2009.11.002
DO - 10.1016/j.cbpb.2009.11.002
M3 - Article
SN - 1096-4959
VL - 155
SP - 178
EP - 185
JO - Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
JF - Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
IS - 2
ER -
