Characterization of a trifunctional fatty acid desaturase from oleaginous filamentous fungus Mortierella alpina 1S-4 using a yeast expression system

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• 作者：Hiroshi Kikukawa ; Eiji Sakuradani ; Shigenobu Kishino ; Si-Bum Park ; Akinori Ando ; Jun Shima ; Misa Ochiai ; Sakayu Shimizu ; Jun Ogawa
• 关键词：Mortierella alpina ; Polyunsaturated fatty acid ; Trifunctional fatty acid desaturase ; Hexadecadienoic acid ; Hexadecatrienoic acid
• 刊名：Journal of Bioscience and Bioengineering
• 出版年：December, 2013
• 年：2013
• 卷：116
• 期：6
• 页码：672-676
• 全文大小：518 K

文摘

A 蠅3-fatty acid desaturase gene (maw3) which is involved in biosynthesis of n-3 polyunsaturated fatty acids (PUFAs) was previously isolated from Mortierella alpina 1S-4. In this report, we investigated the products of MAW3 catalyzing reaction with endogenous and exogenous fatty acids in the yeast transformant. Two unusual fatty acids de novo synthesized in the yeast transformant expressing maw3 gene were identified as n-4 hexadecadienoic acid (16:2^9cis,12cis) and n-1 hexadecatrienoic acid (16:3^{9cis,12cis,15}) by GC-MS and ¹H NMR analyses. In addition to the desaturation activity at the 蠅3-position for 18- and 20-carbon PUFAs, MAW3 in the yeast transformant inserted a double bond at 螖12-position of endogenous palmitoleic acid (16:1^9cis) and further at 螖15-position of the resulting 16:2^9cis,12cis to result in the formation of 16:3^{9cis,12cis,15} leading to a bifunctional 螖12/螖15-desaturase for 16-carbon fatty acids. Moreover, we evaluated the activity of MAW3 in the yeast transformant under different temperatures. The MAW3 did not have desaturation activities in M.聽alpina 1S-4 at 28掳C but it had in the yeast transformant for various fatty acids. The MAW3 was demonstrated to be a trifunctional 螖12/螖15/蠅3-desaturase, exhibiting 螖12-desaturation for 16:1^9cis, 螖15-desaturation for 16- and 18-carbon fatty acids that had a preexisting cis-double bond at 螖12 position, and 蠅3-desaturation for 20-carbon fatty acids having that at 螖14-position. It is the first report that the fatty acid desaturase (MAW3) is shown to have 螖12- and 螖15-desaturation activities for a 16-carbon fatty acid, in addition to its major function, 蠅3-desaturation activity.