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Gene characterized for membrane desaturase that produces (E)-11 isomers of mono- and diunsaturated fatty acids
- Liu, W., Jiao, H., Murray, N.C., O'Connor, M., Roelofs, W.L.
- Proceedings of the National Academy of Sciences of the United States of America 2002 v.99 no.2 pp. 620-624
- Epiphyas postvittana, complementary DNA, amino acid sequences, monounsaturated fatty acids, genes, nucleotide sequences, pheromone glands, dienoic fatty acids, enzyme activity
- Moth species have evolved integral membrane desaturases that exhibit a wide diversity in substrate specificity, as well as in regiospecificity and stereospecificity of the unsaturated products. We report here the cloning and expression of a single desaturase from the sex pheromone gland of the light brown apple moth, Epiphyas postvittana, that makes E11 isomers of monounsaturated (E11-16 and E11-14) fatty acids and a diunsaturated (E9,E11-14) fatty acid. In the pheromone gland, the monoene precursor is made available by beta oxidation of E11-16 acid with a subsequent two-carbon loss to E9-14 acid. A functional assay using a baculovirus expression system required addition of myristic acid and E9-14 acid precursors to demonstrate the unusual regiospecificity and stereospecificity of this desaturase. The amino acid sequence of this desaturase has approximately equal to 61% identity to that of Z11-desaturases from two other insect species, and only approximately equal to 48% identity to the metabolic Z9-desaturases in those species. A pheromone-gland Z9-desaturase gene also was found with the light brown apple moth that differed in its deduced amino acid sequence (66% identity) with the metabolic Z9-desaturase from fat body in this species.