2IWY

Human mitochondrial beta-ketoacyl ACP synthase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.06 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.163 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.4 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: https://doi.org/10.1110/ps.062473707
  • Primary Citation of Related Structures:  
    2IWY, 2IWZ, 2IX4

  • 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 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.


  • Organizational Affiliation

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


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
3-OXOACYL-[ACYL-CARRIER-PROTEIN] SYNTHASE
A, B
438Homo sapiensMutation(s): 0 
EC: 2.3.1.41
UniProt & NIH Common Fund Data Resources
Find proteins for Q9NWU1 (Homo sapiens)
Explore Q9NWU1 
Go to UniProtKB:  Q9NWU1
PHAROS:  Q9NWU1
GTEx:  ENSG00000151093 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9NWU1
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.06 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.163 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 72.626α = 90
b = 96.061β = 90
c = 115.468γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
MOLREPphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-02-06
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2018-01-17
    Changes: Data collection, Database references, Structure summary
  • Version 1.3: 2018-01-24
    Changes: Source and taxonomy
  • Version 1.4: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description