1ES9

X-RAY CRYSTAL STRUCTURE OF R22K MUTANT OF THE MAMMALIAN BRAIN PLATELET-ACTIVATING FACTOR ACETYLHYDROLASES (PAF-AH)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.30 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.192 

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This is version 1.3 of the entry. See complete history


Literature

The functional implications of the dimerization of the catalytic subunits of the mammalian brain platelet-activating factor acetylhydrolase (Ib).

McMullen, T.W.Li, J.Sheffield, P.J.Aoki, J.Martin, T.W.Arai, H.Inoue, K.Derewenda, Z.S.

(2000) Protein Eng 13: 865-871

  • DOI: 10.1093/protein/13.12.865
  • Primary Citation of Related Structures:  
    1ES9

  • PubMed Abstract: 
  • The mammalian brain contains significant amounts of the cytosolic isoform Ib of the platelet-activating factor acetylhydrolase (PAF-AH), a unique type of PLA2. This oligomeric protein complex contains three types of subunits: two homologous (63% identity) 26 kDa catalytic subunits (alpha(1) and alpha(2)) which harbor all the PAF-AH activity, and the 45 kDa beta-subunit (LIS1), a product of the causal gene for Miller-Dieker lissencephaly ...

    The mammalian brain contains significant amounts of the cytosolic isoform Ib of the platelet-activating factor acetylhydrolase (PAF-AH), a unique type of PLA2. This oligomeric protein complex contains three types of subunits: two homologous (63% identity) 26 kDa catalytic subunits (alpha(1) and alpha(2)) which harbor all the PAF-AH activity, and the 45 kDa beta-subunit (LIS1), a product of the causal gene for Miller-Dieker lissencephaly. During fetal development, the preferentially expressed alpha(1)-subunit forms a homodimer, which binds to a homodimer of LIS1, whereas in adult organisms alpha(1)/alpha(2) and alpha(2)/alpha(2) dimers, also bound to dimeric LIS1, are the prevailing species. The consequences of this "switching" are not understood, but appear to be of physiological significance. The alpha(1)- and alpha(2)-subunits readily associate with very high affinity to form homodimers. The nature of the interface has been elucidated by the 1.7 A resolution crystal structure of the alpha(1)/alpha(1) homodimer (Ho et al., 1997). Here, we examined the functional consequences of the dimerization in both types of alpha-subunits. We obtained monomeric protein in the presence of high concentrations (>50 mM) of Ca2+ ions, and we show that it is catalytically inactive and less stable than the wild type. We further show that Arg29 and Arg22 in one monomer contribute to the catalytic competence of the active site across the dimer interface, and complement the catalytic triad of Ser47, Asp192 and His195, in the second monomer. These results indicate that the brain PAF-acetylhydrolase is a unique PLA2 in which dimerization is essential for both stability and catalytic activity.


    Related Citations: 
    • Brain Acetylhydrolase that Inactivates Platelet-activating Factor is a G-protein-like trimer
      Ho, Y.S., Swenson, L., Derewenda, U., Serre, L., Wei, Y., Dauter, Z., Hattori, M., Adachi, T., Aoki, J., Arai, H., Inoue, K., Derewenda, Z.S.
      (1997) Nature 385: 89

    Organizational Affiliation

    Department of Molecular Physiology and Biological Physics, University of Virginia, Health Sciences Center, Charlottesville, VA 22906-0011, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PLATELET-ACTIVATING FACTOR ACETYLHYDROLASE IB GAMMA SUBUNITA232Bos taurusMutation(s): 1 
Gene Names: PAFAH1B3PAFAHG
EC: 3.1.1.47
UniProt
Find proteins for Q29460 (Bos taurus)
Explore Q29460 
Go to UniProtKB:  Q29460
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.30 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.192 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.049α = 90
b = 81.049β = 90
c = 72.662γ = 120
Software Package:
Software NamePurpose
AMoREphasing
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-05-31
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-31
    Changes: Advisory, Experimental preparation