Skip Navigation

This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (6)
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by McMullen, T.W.P.
Right arrow Articles by Derewenda, Z.S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by McMullen, T.W.P.
Right arrow Articles by Derewenda, Z.S.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Protein Engineering, Vol. 13, No. 12, 865-871, December 2000
© 2000 Oxford University Press

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

T.W.P. McMullen1, J. Li1, P.J. Sheffield1, J. Aoki2, T.W. Martin1, H. Arai2, K. Inoue2 and Z.S. Derewenda1,3

1 Department of Molecular Physiology and Biological Physics, University of Virginia, Health Sciences Center, Charlottesville, VA 22906-0011, USA and 2 Department of Health Chemistry, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan

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 ß-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 Å 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.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
T. M. Bjerkan, C. L. Bender, H. Ertesvag, F. Drablos, M. K. Fakhr, L. A. Preston, G. Skjak-Braek, and S. Valla
The Pseudomonas syringae Genome Encodes a Combined Mannuronan C-5-epimerase and O-Acetylhydrolase, Which Strongly Enhances the Predicted Gel-forming Properties of Alginates
J. Biol. Chem., July 9, 2004; 279(28): 28920 - 28929.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
G. Liu, C. Jin, and C. Jin
CMP-N-Acetylneuraminic Acid Synthetase from Escherichia coli K1 Is a Bifunctional Enzyme: IDENTIFICATION OF MINIMAL CATALYTIC DOMAIN FOR SYNTHETASE ACTIVITY AND NOVEL FUNCTIONAL DOMAIN FOR PLATELET-ACTIVATING FACTOR ACETYLHYDROLASE ACTIVITY
J. Biol. Chem., April 23, 2004; 279(17): 17738 - 17749.
[Abstract] [Full Text] [PDF]

Home page
 Protein Eng Des SelHome page
P. J. Sheffield, T. W.P. McMullen, J. Li, Y.-S. Ho, S. M. Garrard, U. Derewenda, and Z. S. Derewenda
Preparation and crystal structure of the recombinant {alpha}1/{alpha}2 catalytic heterodimer of bovine brain platelet-activating factor acetylhydrolase Ib
Protein Eng. Des. Sel., July 1, 2001; 14(7): 513 - 519.
[Abstract] [Full Text] [PDF]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.