Lysine as a Critical Amino Acid for IgE Binding in Phl p 5b C Terminus
| Autor: | Eckhard Hofmann, K. R. Rajashankar, Albrecht Bufe, Wolfgang Weber, Sandra Werner, Christian Betzel, Kirsten Gehlhar |
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| Rok vydání: | 2006 |
| Předmět: |
Molecular Sequence Data
Immunology Lysine chemical and pharmacologic phenomena macromolecular substances Immunoglobulin E Binding Competitive Epitope Antigen-Antibody Reactions Ribonucleases Humans Immunology and Allergy Amino Acid Sequence Pyrophosphatases Binding site Plant Proteins Skin Tests chemistry.chemical_classification Binding Sites biology Phosphoric Diester Hydrolases Circular Dichroism C-terminus technology industry and agriculture hemic and immune systems General Medicine Allergens Recombinant Proteins Basophils Amino acid Basophilic chemistry Biochemistry Immunoglobulin G Mutagenesis Site-Directed biology.protein Antibody |
| Zdroj: | International Archives of Allergy and Immunology. 140:285-294 |
| ISSN: | 1423-0097 1018-2438 |
| Popis: | Background: Allergens induce the formation of specific immunoglobulin (Ig)E and harbor at least two IgE-binding regions (epitopes) to facilitate crosslinking of basophilic or mast-cell-bound specific IgE antibodies. Studies mapping linear epitopes have shown that these regions often contain charged or hydrophobic amino acids. Nevertheless, these studies are hampered by limited significance due to the often conformational nature of IgE epitopes. This prompted us to study the role of lysines in the context of an intact 3-dimensional model. Methods: Major allergen Phl p 5b from timothy grass bears 12 lysines in its C-terminal half. Using site-directed mutagenesis, we substituted all 10 surface-exposed lysines by alanines. Results: Although structural integrity of the lysine-deficient mutant was not altered, IgE-binding capacity measured by ELISA inhibition tests and crosslinking activity in ex vivo basophil stimulation and in vivo skin prick tests were significantly diminished. Interestingly, binding of specific IgG antibodies was considerably less reduced by loss of lysines. Conclusion: Lysine is an important amino acid for IgE binding in more than one epitope of major grass pollen allergen Phl p 5b C terminus. Allergenicity, but not IgG binding of the molecule, is substantially diminished by single amino acid substitutions without structural integrity being hampered. |
| Databáze: | OpenAIRE |
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