2IX4

Arabidopsis thaliana mitochondrial beta-ketoacyl ACP synthase hexanoic acid complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.195 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of the Human Beta-Ketoacyl [Acp] Synthase from the Mitochondrial Type II Fatty Acid Synthase.

Christensen, C.E.Kragelund, B.B.von Wettstein-Knowles, P.Henriksen, A.

(2007) Protein Sci. 16: 261-272

  • DOI: 10.1110/ps.062473707
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Two distinct ways of organizing fatty acid biosynthesis exist: the multifunctional type I fatty acid synthase (FAS) of mammals, fungi, and lower eukaryotes with activities residing on one or two polypeptides; and the dissociated type II FAS of prokar ...

    Two distinct ways of organizing fatty acid biosynthesis exist: the multifunctional type I fatty acid synthase (FAS) of mammals, fungi, and lower eukaryotes with activities residing on one or two polypeptides; and the dissociated type II FAS of prokaryotes, plastids, and mitochondria with individual activities encoded by discrete genes. The beta-ketoacyl [ACP] synthase (KAS) moiety of the mitochondrial FAS (mtKAS) is targeted by the antibiotic cerulenin and possibly by the other antibiotics inhibiting prokaryotic KASes: thiolactomycin, platensimycin, and the alpha-methylene butyrolactone, C75. The high degree of structural similarity between mitochondrial and prokaryotic KASes complicates development of novel antibiotics targeting prokaryotic KAS without affecting KAS domains of cytoplasmic FAS. KASes catalyze the C(2) fatty acid elongation reaction using either a Cys-His-His or Cys-His-Asn catalytic triad. Three KASes with different substrate specificities participate in synthesis of the C(16) and C(18) products of prokaryotic FAS. By comparison, mtKAS carries out all elongation reactions in the mitochondria. We present the X-ray crystal structures of the Cys-His-His-containing human mtKAS and its hexanoyl complex plus the hexanoyl complex of the plant mtKAS from Arabidopsis thaliana. The structures explain (1) the bimodal (C(6) and C(10)-C(12)) substrate preferences leading to the C(8) lipoic acid precursor and long chains for the membranes, respectively, and (2) the low cerulenin sensitivity of the human enzyme; and (3) reveal two different potential acyl-binding-pocket extensions. Rearrangements taking place in the active site, including subtle changes in the water network, indicate a change in cooperativity of the active-site histidines upon primer binding.


    Related Citations: 
    • Structure of Mitochondrial Beta-Ketoacyl-(Acyl Carrier Protein) Synthase from Arabidopsis and its Role in Fatty Acid Synthesis
      Olsen, J.G.,Rasmussen, A.V.,von Wettstein-Knowles, P.,Henriksen, A.
      (2004) FEBS Lett. 577: 170


    Organizational Affiliation

    Department of Molecular Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
3-OXOACYL-[ACYL-CARRIER-PROTEIN] SYNTHASE
A, B
431Arabidopsis thalianaMutation(s): 0 
Gene Names: KAS
EC: 2.3.1.41
Find proteins for Q8L3X9 (Arabidopsis thaliana)
Go to UniProtKB:  Q8L3X9
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
A, B
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
6NA
Query on 6NA

Download SDF File 
Download CCD File 
A, B
HEXANOIC ACID
C6 H12 O2
FUZZWVXGSFPDMH-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.195 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 72.109α = 90.00
b = 92.942β = 106.59
c = 74.217γ = 90.00
Software Package:
Software NamePurpose
MOLREPphasing
SCALAdata scaling
REFMACrefinement
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-02-06
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.2: 2018-01-17
    Type: Database references, Structure summary