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Title: Crystal Structure of a Dimerized Cockroach Allergen Bla g 2 Complexed with a Monoclonal Antibody

Abstract

The crystal structure of a 1:1 complex between the German cockroach allergen Bla g 2 and the Fab' fragment of a monoclonal antibody 7C11 was solved at 2.8-{angstrom} resolution. Bla g 2 binds to the antibody through four loops that include residues 60-70, 83-86, 98-100, and 129-132. Cation-{pi} interactions exist between Lys-65, Arg-83, and Lys-132 in Bla g 2 and several tyrosines in 7C11. In the complex with Fab', Bla g 2 forms a dimer, which is stabilized by a quasi-four-helix bundle comprised of an {alpha}-helix and a helical turn from each allergen monomer, exhibiting a novel dimerization mode for an aspartic protease. A disulfide bridge between C51a and C113, unique to the aspartic protease family, connects the two helical elements within each Bla g 2 monomer, thus facilitating formation of the bundle. Mutation of these cysteines, as well as the residues Asn-52, Gln-110, and Ile-114, involved in hydrophobic interactions within the bundle, resulted in a protein that did not dimerize. The mutant proteins induced less {beta}-hexosaminidase release from mast cells than the wild-type Bla g 2, suggesting a functional role of dimerization in allergenicity. Because 7C11 shares a binding epitope with IgE, the information gained by analysis of themore » crystal structure of its complex provided guidance for site-directed mutagenesis of the allergen epitope. We have now identified key residues involved in IgE antibody binding; this information will be useful for the design of vaccines for immunotherapy.« less

Authors:
; ; ; ; ; ; ;  [1];  [2];  [2]
  1. (INDOOR Bio.)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1006782
Resource Type:
Journal Article
Journal Name:
J. Biol. Chem.
Additional Journal Information:
Journal Volume: 283; Journal Issue: (33) ; 08, 2008; Journal ID: ISSN 0021-9258
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; CRYSTAL STRUCTURE; DESIGN; DIMERIZATION; DISULFIDES; FUNCTIONALS; IMMUNOTHERAPY; MAST CELLS; MUTAGENESIS; MUTANTS; MUTATIONS; PROTEINS; RESIDUES; RESOLUTION; VACCINES

Citation Formats

Li, Mi, Gustchina, Alla, Alexandratos, Jerry, Wlodawer, Alexander, Wünschmann, Sabina, Kepley, Christopher L., Chapman, Martin D., Pomes, Anna, VCU), and NIH). Crystal Structure of a Dimerized Cockroach Allergen Bla g 2 Complexed with a Monoclonal Antibody. United States: N. p., 2008. Web. doi:10.1074/jbc.M800937200.
Li, Mi, Gustchina, Alla, Alexandratos, Jerry, Wlodawer, Alexander, Wünschmann, Sabina, Kepley, Christopher L., Chapman, Martin D., Pomes, Anna, VCU), & NIH). Crystal Structure of a Dimerized Cockroach Allergen Bla g 2 Complexed with a Monoclonal Antibody. United States. doi:10.1074/jbc.M800937200.
Li, Mi, Gustchina, Alla, Alexandratos, Jerry, Wlodawer, Alexander, Wünschmann, Sabina, Kepley, Christopher L., Chapman, Martin D., Pomes, Anna, VCU), and NIH). Wed . "Crystal Structure of a Dimerized Cockroach Allergen Bla g 2 Complexed with a Monoclonal Antibody". United States. doi:10.1074/jbc.M800937200.
@article{osti_1006782,
title = {Crystal Structure of a Dimerized Cockroach Allergen Bla g 2 Complexed with a Monoclonal Antibody},
author = {Li, Mi and Gustchina, Alla and Alexandratos, Jerry and Wlodawer, Alexander and Wünschmann, Sabina and Kepley, Christopher L. and Chapman, Martin D. and Pomes, Anna and VCU) and NIH)},
abstractNote = {The crystal structure of a 1:1 complex between the German cockroach allergen Bla g 2 and the Fab' fragment of a monoclonal antibody 7C11 was solved at 2.8-{angstrom} resolution. Bla g 2 binds to the antibody through four loops that include residues 60-70, 83-86, 98-100, and 129-132. Cation-{pi} interactions exist between Lys-65, Arg-83, and Lys-132 in Bla g 2 and several tyrosines in 7C11. In the complex with Fab', Bla g 2 forms a dimer, which is stabilized by a quasi-four-helix bundle comprised of an {alpha}-helix and a helical turn from each allergen monomer, exhibiting a novel dimerization mode for an aspartic protease. A disulfide bridge between C51a and C113, unique to the aspartic protease family, connects the two helical elements within each Bla g 2 monomer, thus facilitating formation of the bundle. Mutation of these cysteines, as well as the residues Asn-52, Gln-110, and Ile-114, involved in hydrophobic interactions within the bundle, resulted in a protein that did not dimerize. The mutant proteins induced less {beta}-hexosaminidase release from mast cells than the wild-type Bla g 2, suggesting a functional role of dimerization in allergenicity. Because 7C11 shares a binding epitope with IgE, the information gained by analysis of the crystal structure of its complex provided guidance for site-directed mutagenesis of the allergen epitope. We have now identified key residues involved in IgE antibody binding; this information will be useful for the design of vaccines for immunotherapy.},
doi = {10.1074/jbc.M800937200},
journal = {J. Biol. Chem.},
issn = {0021-9258},
number = (33) ; 08, 2008,
volume = 283,
place = {United States},
year = {2008},
month = {9}
}