Heterologous reconstitution in yeast of the polyunsaturated fatty acid biosynthetic pathway.
A Caenorhabditis elegans ORF encoding the presumptive condensing enzyme activity of a fatty acid elongase has been characterized functionally by heterologous expression in yeast. This ORF (F56H11. 4) shows low similarity to Saccharomyces cerevisiae genes involved in fatty acid elongation. The substrate specificity of the C. elegans enzyme indicated a preference for Delta(6)-desaturated C18 polyunsaturated fatty acids. Coexpression of this activity with fatty acid desaturases required for the synthesis of C20 polyunsaturated fatty acids resulted in the accumulation of arachidonic acid from linoleic acid and eicosapentaenoic acid from alpha-linolenic acid. These results demonstrate the reconstitution of the n-3 and n-6 polyunsaturated fatty acid biosynthetic pathways. The C. elegans ORF is likely to interact with endogenous components of a yeast elongation system, with the heterologous nematode condensing enzyme F56H11.4 causing a redirection of enzymatic activity toward polyunsaturated C18 fatty acid substrates.
Beaudoin
F
F
Institute of Arable Crops Research, Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Long Ashton, Bristol BS41 9AF, United Kingdom.
Michaelson
L V
LV
Hey
S J
SJ
Lewis
M J
MJ
Shewry
P R
PR
Sayanova
O
O
Napier
J A
JA
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000235:genetics*; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013379:Substrate Specificity
D005231:Fatty Acids, Unsaturated; D044943:Fatty Acid Desaturases