Substrate specificity of Arabidopsis 3-ketoacyl-CoA synthases

Biochem Biophys Res Commun. 2006 Jul 28;346(2):583-90. doi: 10.1016/j.bbrc.2006.05.162.

Abstract

The very long chain fatty acids (VLCFA) incorporated into plant lipids are derived from the iterative addition of C2 units provided by malonyl-CoA to an acyl-CoA by the 3-ketoacyl-CoA synthase (KCS) component of a fatty acid elongase (FAE) complex. Mining of the Arabidopsis genome sequence database revealed 20 genes with homology to seed-specific FAE1 KCS. Eight of the 20 putative KCSs were cloned, expressed in yeast, and isolated as (His)6 fusion proteins. Five of the eight (At1g71160, At1g19440, At1g07720, At5g04530, and At4g34250) had little or no activity with C16 to C20 substrates while three demonstrated activity with C16, C18, and C20 saturated acyl-CoA substrates. At1g01120 KCS (KCS1) and At2g26640 KCS had broad substrate specificities when assayed with saturated and mono-unsaturated C16 to C24 acyl-CoAs while At4g34510 KCS was specific for saturated fatty acyl-CoA substrates.

MeSH terms

  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / genetics
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / metabolism*
  • Acetyltransferases / genetics
  • Acetyltransferases / metabolism*
  • Amino Acid Sequence
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cloning, Molecular
  • Fatty Acid Elongases
  • Fatty Acids / metabolism
  • Fatty Acids, Unsaturated / metabolism
  • Histidine / genetics
  • Molecular Sequence Data
  • Phylogeny
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Substrate Specificity
  • Yeasts / genetics
  • Yeasts / metabolism

Substances

  • Arabidopsis Proteins
  • Fatty Acids
  • Fatty Acids, Unsaturated
  • Recombinant Fusion Proteins
  • Histidine
  • Acetyltransferases
  • Fatty Acid Elongases
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase