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PDBsum entry 1b6u
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Killer cell inhibitory receptor
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PDB id
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1b6u
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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 human p58 killer cell inhibitory receptor (kir2dl3) specific for hla-Cw3-Related mhc class i.
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Authors
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K.Maenaka,
T.Juji,
D.I.Stuart,
E.Y.Jones.
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Ref.
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Structure, 1999,
7,
391-398.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
91%.
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Abstract
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BACKGROUND: T cells and natural killer (NK) cells perform complementary roles in
the cellular immune system. T cells identify infected cells directly through
recognition of antigenic peptides that are displayed at the target cell surface
by the classical major histocompatibility complex (MHC) class I molecules. NK
cells monitor the target cell surface for malfunction of this display system,
lysing potentially infected cells that might otherwise evade recognition by the
T cells. Human killer cell inhibitory receptors (KIRs) control this process by
either inhibiting or activating the cytotoxic activity of NK cells via specific
binding to MHC class I molecules on the target cell. RESULTS: We report the
crystal structure of the extracellular region of the human p58 KIR (KIR2DL3),
which is specific for the human MHC class I molecule HLA-Cw3 and related
alleles. The structure shows the predicted topology of two tandem
immunoglobulin-like domains, but comparison with the previously reported
structure of the related receptor KIR2DL1 reveals an unexpected change of 23
degrees in the relative orientation of these domains. CONCLUSIONS: The altered
orientation of the immunoglobulin-like domains maintains an unusually acute
interdomain elbow angle, which therefore appears to be a distinctive feature of
the KIRs. The putative MHC class I binding site is located on the outer surface
of the elbow, spanning both domains. The unexpected observation that this
binding site can be modulated by differences in the relative domain orientations
has implications for the general mechanism of KIR-MHC class I complex formation.
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Figure 3.
Figure 3. Comparison of KIR2DL3 and KIR2DL1 structures. (a)
Comparison of the D1-D2 orientation in KIR2DL3 (red) and KIR2DL1
(green). Ca traces for superposition based on D2 are shown in
two orthogonal views. (b) Comparison of the D1-D2 interface in
KIR2DL3 (grey with sidechain atoms coloured orange, blue and red
for C, N and O, respectively) and KIR2DL1 (green). Key residue
sidechains are shown in ball-and-stick representation. The mauve
mesh depicts the sidechain electron density for residues 17,
100, 102, 178 and 188, for which the sidechain atoms beyond Ca
were omitted from the phasing model (2F[o]-F[c] map contoured at
1s).
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The above figure is
reprinted
by permission from Cell Press:
Structure
(1999,
7,
391-398)
copyright 1999.
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