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Title
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The crystal structure of IgE Fc reveals an asymmetrically bent conformation.
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Authors
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T.Wan,
R.L.Beavil,
S.M.Fabiane,
A.J.Beavil,
M.K.Sohi,
M.Keown,
R.J.Young,
A.J.Henry,
R.J.Owens,
H.J.Gould,
B.J.Sutton.
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Ref.
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Nat Immunol, 2002,
3,
681-686.
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PubMed id
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Abstract
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The distinguishing structural feature of immunoglobulin E (IgE), the antibody
responsible for allergic hypersensitivity, is the C epsilon 2 domain pair that
replaces the hinge region of IgG. The crystal structure of the IgE Fc (constant
fragment) at a 2.6-A resolution has revealed these domains. They display a
distinctive, disulfide-linked Ig domain interface and are folded back
asymmetrically onto the C epsilon 3 and C epsilon 4 domains, which causes an
acute bend in the IgE molecule. The structure implies that a substantial
conformational change involving C epsilon 2 must accompany binding to the mast
cell receptor Fc epsilon RI. This may be the basis of the exceptionally slow
dissociation rate of the IgE-Fc epsilon RI complex and, thus, of the ability of
IgE to cause persistent allergic sensitization of mast cells.
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