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PDBsum entry 1uct
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Immune system
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PDB id
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1uct
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Crystal structure of the ectodomain of human fcalphari.
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Authors
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Y.Ding,
G.Xu,
M.Yang,
M.Yao,
G.F.Gao,
L.Wang,
W.Zhang,
Z.Rao.
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Ref.
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J Biol Chem, 2003,
278,
27966-27970.
[DOI no: ]
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PubMed id
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Abstract
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Human FcalphaRI (CD89) is the receptor specific for IgA, an immunoglobulin that
is abundant in mucosa and is also found in high concentrations in serum.
Although FcalphaRI is an immunoglobulin Fc receptor (FcR), it differs in many
ways from FcRs for other immunoglobulin classes. The genes of most FcRs are
located on chromosome 1 at 1q21-23, whereas FcalphaRI is on chromosome 19, at
19q13.4, a region called the leukocyte receptor complex, because it is clustered
with several leukocyte receptor families including killer cell inhibitory
receptors (KIRs) and leukocyte Ig-like receptors (LIRs). The amino acid sequence
of FcalphaRI shares only 20% homology with other FcRs but it has around 35%
homology with its neighboring LIRs and KIRs. In this work, we analyzed the
crystal structure of the ectodomain of FcalphaRI and examined structure
similarities between FcalphaRI and KIR2DL1, KIR2DL2 and LIR-1. Our data show
that FcalphaRI, KIRs, and LIRs share a common hydrophobic core in their
interdomain interface, and FcalphaRI is evolutionally closer to LIR than KIR.
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Figure 1.
FIG. 1. Crystal structure of Fc  RI ectodomain. a,
stereo ribbon drawing of the structure of Fc RI. EC1 is the
N-terminal domain, and EC2 is the C-terminal domain. Disulfide
bonds are shown in green. The residues 56-59 and 196-199 were
disordered in the electron density map. b, topological diagram
of the ectodomain of Fc RI. The arrows show the
directions of  -strands, whereas the
3[10] helix structures are represented by two circles. The amino
acid residues at each end of -strands and helices are
numbered. c, close-up stereo view of the hydrophobic core in the
interdomain interface of Fc RI. The 12 residues
responsible for stabilizing the hydrophobic core are shown in
ball-and-stick representation. Tyr173 (Y173) is colored yellow,
Tyr181 (Y181) blue, and Trp183 (W183) green. Other residues are
colored using the CPK (Corey-Pauling-Kendrew) convention (blue,
nitrogen; red, oxygen; gray, carbon; yellow, sulfur) color
scheme.
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Figure 4.
FIG. 4. Residues involved in Fc RI binding of IgA. a,
position of the potential binding area on Fc RI. b, molecular
surface of Fc RI. The residues
involved in binding of IgA are highlighted in color. Tyr35 is
colored red, Asn44 brown, Arg52 pink, Arg82 blue, Ile^83 green,
Gly84 dark blue, His85 orange, and Tyr87 purple. The structure
was represented by DeepView Swiss-PdbViewer (34).
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2003,
278,
27966-27970)
copyright 2003.
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