Delta 9 Acyl-lipid Desaturases of Cyanobacteria. Molecular Cloning and Substrate Specificities in Terms of Fatty Acids, Sn-Positions, and Polar Head Groups

J Biol Chem. 1994 Oct 14;269(41):25576-80.

Abstract

In cyanobacteria, the biosynthesis of unsaturated fatty acids is initiated by delta 9 acyl-lipid desaturase which introduces the first double bond at the delta 9 position of a saturated fatty acid that has been esterified to a glycerolipid. We have cloned genes, designated desC, for delta 9 acyl-lipid desaturases from two cyanobacteria, namely Anabaena variabilis and Synechocystis sp. PCC 6803. These desaturases, when expressed in Escherichia coli, desaturated stearic acid to yield oleic acid at the C-1 positions of phosphatidylethanolamine and phosphatidylglycerol, but did not desaturate palmitic acid, palmitoleic acid, and cis-vaccenic acid. These results indicate that the delta 9 acyl-lipid desaturases are specific to stearic acid esterified at the C-1 position of a glycerolipid and are nonspecific with respect to the polar head group of the glycerolipid. The deduced amino acid sequences of the delta 9 acyl-lipid desaturases are similar in part to those of stearoyl-CoA desaturases of the rat, the mouse, and Saccharomyces cerevisiae, but not to those of acyl-(acyl-carrier-protein) desaturases of higher plants.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anabaena / enzymology
  • Anabaena / genetics*
  • Base Sequence
  • Cloning, Molecular
  • Cyanobacteria / enzymology
  • Cyanobacteria / genetics*
  • Escherichia coli / genetics
  • Fatty Acid Desaturases / biosynthesis
  • Fatty Acid Desaturases / genetics*
  • Fatty Acid Desaturases / metabolism
  • Fatty Acids / metabolism
  • Genes, Bacterial / genetics*
  • Lipids / chemistry
  • Molecular Sequence Data
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / metabolism
  • Restriction Mapping
  • Sequence Homology, Amino Acid
  • Stearoyl-CoA Desaturase
  • Substrate Specificity

Substances

  • Fatty Acids
  • Lipids
  • Recombinant Proteins
  • Fatty Acid Desaturases
  • Stearoyl-CoA Desaturase
  • delta-9 fatty acid desaturase

Associated data

  • GENBANK/D16547