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Lipopolysaccharide binding of the mite allergen Der f 2
Author(s) -
Ichikawa Saori,
Takai Toshiro,
Yashiki Tomoe,
Takahashi Seizo,
Okumura Ko,
Ogawa Hideoki,
Kohda Daisuke,
Hatanaka Hideki
Publication year - 2009
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2009.01334.x
Subject(s) - biology , lipopolysaccharide , toll like receptor , ligand (biochemistry) , allergen , innate immune system , binding site , receptor , lipid a , tlr4 , house dust mite , biochemistry , immunology , allergy
Lipid‐binding properties and/or involvement with host defense are often found in allergen proteins, implying that these intrinsic biological functions likely contribute to the allergenicity of allergens. The group 2 major mite allergens, Der f 2 and Der p 2, show structural homology with MD‐2, the lipopolysaccharide (LPS)‐binding component of the Toll‐like receptor (TLR) 4 signalling complex. Elucidation of the ligand‐binding properties of group 2 mite allergens and identification of interaction sites by structural studies are important to explore the relationship between allergenicity and biological function. Here, we report a ligand‐fishing approach in which His‐tagged Der f 2 was incubated with sonicated stable isotope‐labelled Escherichia coli as a potential ligand source, followed by isolation of Der f 2‐bound material by a HisTrap column and NMR analysis. We found that Der f 2 binds to LPS with a nanomolar affinity and, using fluorescence and gel filtration assays that LPS binds to Der f 2 in a molar ratio of 1 : 1. We mapped the LPS‐binding interface of Der f 2 by NMR perturbation studies, which suggested that LPS binds Der f 2 between the two large β‐sheets, similar to its binding to MD‐2, the LPS‐binding component of the innate immunity receptor TLR4.