Function and Biology

CRYSTAL STRUCTURE OF BETA-KETOACYL-[ACYL CARRIER PROTEIN] SYNTHASE I FROM ESCHERICHIA COLI

Source organism: Escherichia coli
Biochemical function: transferase activity
Biological process: fatty acid biosynthetic process
Cellular component: cytosol

EC 2.3.1.41: Beta-ketoacyl-[acyl-carrier-protein] synthase I

Reaction catalysed:
Acyl-[acyl-carrier-protein] + malonyl-[acyl-carrier-protein] = 3-oxoacyl- [acyl-carrier-protein] + CO(2) + [acyl-carrier-protein].
Comments:
  • Responsible for the chain-elongation step of dissociated (type II) fatty-acid biosynthesis, i.e. the addition of two C atoms to the fatty-acid chain.
  • Escherichia coli mutants that lack this enzyme are deficient in unsaturated fatty acids.
  • Can use fatty acyl thioesters of ACP (C(2) to C(16)) as substrates, as well as fatty acyl thioesters of Co-A (C(4) to C(16)).
  • The substrate specificity is very similar to that of EC 2.3.1.179 with the exception that the latter enzyme is far more active with palmitoleoyl-ACP (C(16)-Delta(9)) as substrate, allowing the organism to regulate its fatty-acid composition with changes in temperature.
Systematic name:
Acyl-[acyl-carrier protein]:malonyl-[acyl-carrier protein] C-acyltransferase (decarboxylating)
Alternative Name(s):
  • 3-ketoacyl-acyl carrier protein synthase
  • Beta-ketoacyl acyl carrier protein synthase
  • Beta-ketoacyl synthetase
  • Beta-ketoacyl-ACP synthetase
  • Beta-ketoacyl-[acyl carrier protein] synthase
  • Beta-ketoacyl-acyl carrier protein synthetase
  • Beta-ketoacylsynthase
  • Acyl-malonyl(acyl-carrier-protein)-condensing enzyme
  • Condensing enzyme
  • Fatty acid condensing enzyme
  • Beta-ketoacyl-ACP synthase I
  • Acyl-malonyl acyl carrier protein-condensing enzyme
  • 3-oxoacyl-[acyl-carrier-protein] synthase
  • 3-oxoacyl:ACP synthase I
  • KASI
  • KAS I
  • FabF1
  • FabB
  • Acyl-[acyl-carrier-protein]:malonyl-[acyl-carrier-protein] C-acyltransferase (decarboxylating)

Sequence families

Pfam Protein families (Pfam)
PF00109
Domain description: Beta-ketoacyl synthase, N-terminal domain
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
1 copy of Pfam domain PF00109 (Beta-ketoacyl synthase, N-terminal domain) in 3-oxoacyl-[acyl-carrier-protein] synthase 1 in PDB 1dd8.

PF02801
Domain description: Beta-ketoacyl synthase, C-terminal domain
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
1 copy of Pfam domain PF02801 (Beta-ketoacyl synthase, C-terminal domain) in 3-oxoacyl-[acyl-carrier-protein] synthase 1 in PDB 1dd8.

InterPro InterPro annotations
IPR016039
Domain description: Thiolase-like
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
IPR014031
Domain description: Beta-ketoacyl synthase, C-terminal
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
IPR020841
Domain description: Polyketide synthase, beta-ketoacyl synthase domain
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
IPR018201
Domain description: Beta-ketoacyl synthase, active site
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
IPR014030
Domain description: Beta-ketoacyl synthase, N-terminal
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1

Structure domain

CATH CATH domain
3.40.47.10
Class: Alpha Beta
Architecture: 3-Layer(aba) Sandwich
Topology: Peroxisomal Thiolase; Chain A, domain 1
Homology: Peroxisomal Thiolase; Chain A, domain 1
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
2 copies of CATH domain 3.40.47.10 (Peroxisomal Thiolase; Chain A, domain 1) in 3-oxoacyl-[acyl-carrier-protein] synthase 1 in PDB 1dd8.
SCOP SCOP annotation
53902
Class: Alpha and beta proteins (a/b)
Fold: Thiolase-like
Superfamily: Thiolase-like
Occurring in:
  1. 3-oxoacyl-[acyl-carrier-protein] synthase 1
2 copies of SCOP domain 53902 (Thiolase-related) in 3-oxoacyl-[acyl-carrier-protein] synthase 1 in PDB 1dd8.