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: 1.3 Å
  • R-Value Free: 0.217 
  • R-Value Work: 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


  • 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% iden ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PLATELET-ACTIVATING FACTOR ACETYLHYDROLASE IB GAMMA SUBUNIT
A
232Bos taurusMutation(s): 1 
Gene Names: PAFAH1B3 (PAFAHG)
EC: 3.1.1.47
Find proteins for Q29460 (Bos taurus)
Go to Gene View: PAFAH1B3
Go to UniProtKB:  Q29460
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.3 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.192 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 81.049α = 90.00
b = 81.049β = 90.00
c = 72.662γ = 120.00
Software Package:
Software NamePurpose
DENZOdata reduction
REFMACrefinement
AMoREphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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