Isolation of a Δ6-desaturase gene from the cyanobacteriumSynechocystissp. strain PCC 6803 by gain-of-function expression inAnabaenasp.strain PCC 7120
✍ Scribed by Avutu S. Reddy; Michael L. Nuccio; Lisa M. Gross; Terry L. Thomas
- Publisher
- Springer
- Year
- 1993
- Tongue
- English
- Weight
- 571 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0167-4412
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✦ Synopsis
The enzyme A6-desaturase is responsible for the conversion of linoleic acid (18:2) to 7-1inolenic acid (18:37). A cyanobacterial gene encoding A6-desaturase was cloned by expression of a Synechocystis genomic cosmid library in Anabaena, a cyanobacterium lacking A6-desaturase. Expression of the Synechocystis A6-desaturase gene in Anabaena resulted in the accumulation of 7-1inolenic acid (GLA) and octadecatetraenoic acid (18:4). The predicted 359 amino acid sequence of the Synechocystis A6-desaturase shares limited, but significant, sequence similarity with two other reported desaturases. Analysis of three overlapping cosmids revealed a A12-desaturase gene linked to the A6-desaturase gene. Expression of Synechocystis A 6-and A12-desaturases in Synechococcus, a cyanobacterium deficient in both desaturases, resulted in the production of linoleic acid and 7-1inolenic acid.