Isolation of a delta 6-desaturase gene from the cyanobacterium Synechocystis sp. strain PCC 6803 by gain-of-function expression in Anabaena sp. strain PCC 7120.
The enzyme delta 6-desaturase is responsible for the conversion of linoleic acid (18:2) to gamma-linolenic acid (18:3 gamma). A cyanobacterial gene encoding delta 6-desaturase was cloned by expression of a Synechocystis genomic cosmid library in Anabaena, a cyanobacterium lacking delta 6-desaturase. Expression of the Synechocystis delta 6-desaturase gene in Anabaena resulted in the accumulation of gamma-linolenic acid (GLA) and octadecatetraenoic acid (18:4). The predicted 359 amino acid sequence of the Synechocystis delta 6-desaturase shares limited, but significant, sequence similarity with two other reported desaturases. Analysis of three overlapping cosmids revealed a delta 12-desaturase gene linked to the delta 6-desaturase gene. Expression of Synechocystis delta 6- and delta 12-desaturases in Synechococcus, a cyanobacterium deficient in both desaturases, resulted in the production of linoleic acid and gamma-linolenic acid.
Department of Biology, Texas A&M University, College Station 77843.
A S
AS
Reddy
M L
ML
Nuccio
L M
LM
Gross
T L
TL
Thomas
D000595:Amino Acid Sequence; D017033:Anabaena / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D000458:Cyanobacteria / Q000235:genetics*; D044943:Fatty Acid Desaturases / Q000096:biosynthesis / Q000235:genetics*; D005231:Fatty Acids, Unsaturated / Q000032:analysis; D005798:Genes, Bacterial / Q000235:genetics*; D008040:Genetic Linkage; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism*; D008042:Linolenic Acids / Q000032:analysis; D050602:Linoleoyl-CoA Desaturase; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D014170:Transformation, Genetic; D017965:gamma-Linolenic Acid
D005231:Fatty Acids, Unsaturated; D008041:Linoleic Acids; D008042:Linolenic Acids; D017965:gamma-Linolenic Acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase; C040448:delta-12 fatty acid desaturase; C013641:parinaric acid