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PDBsum entry 2dl2
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Immune system
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PDB id
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2dl2
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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 hla-Cw3 allotype-Specific killer cell inhibitory receptor kir2dl2.
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Authors
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G.A.Snyder,
A.G.Brooks,
P.D.Sun.
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Ref.
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Proc Natl Acad Sci U S A, 1999,
96,
3864-3869.
[DOI no: ]
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PubMed id
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Abstract
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Killer cell inhibitory receptors (KIR) protect class I HLAs expressing target
cells from natural killer (NK) cell-mediated lysis. To understand the molecular
basis of this receptor-ligand recognition, we have crystallized the
extracellular ligand-binding domains of KIR2DL2, a member of the Ig superfamily
receptors that recognize HLA-Cw1, 3, 7, and 8 allotypes. The structure was
determined in two different crystal forms, an orthorhombic P212121 and a
trigonal P3221 space group, to resolutions of 3.0 and 2.9 A, respectively. The
overall fold of this structure, like KIR2DL1, exhibits K-type Ig topology with
cis-proline residues in both domains that define beta-strand switching, which
sets KIR apart from the C2-type hematopoietic growth hormone receptor fold. The
hinge angle of KIR2DL2 is approximately 80 degrees, 14 degrees larger than that
observed in KIR2DL1 despite the existence of conserved hydrophobic residues near
the hinge region. There is also a 5 degrees difference in the observed hinge
angles in two crystal forms of 2DL2, suggesting that the interdomain hinge angle
is not fixed. The putative ligand-binding site is formed by residues from
several variable loops with charge distribution apparently complementary to that
of HLA-C. The packing of the receptors in the orthorhombic crystal form offers
an intriguing model for receptor aggregation on the cell surface.
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Figure 1.
Fig. 1. (A) Ribbon diagram of 2DL2 structure. The
secondary structure assignment for the strands in D1 domain are
A (8-12), A' (16-19), B (23-30), C (36-43), C' (46-52), D
(53-56), E (60-67), F (75-82), and G (90-101). The strands for
the D2 domain are: A (108-111), A' (116-119), B (123-130), C
(135-142), C' (145-152), D (153-156), E (160-167), F (172-180),
and G (188-198), respectively. This figure and other structural
figures were prepared by using the program MOLSCRIPT 2.1 and
RASTER3D (55, 56). The region around cis-Pro-14 (B) and
cis-Pro-114 (C) shows the kink at the proline residue and the
 -hairpin.
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Figure 2.
Fig. 2. (A) Stereo drawing showing the structure overlay
between 2DL1 (in red) and 2DL2 (in green) with their D2 domains
superimposed. The hinge angles, calculated with the program
HINGE, are 66° and 80° for 2DL1 and 2DL2, respectively.
Residues involved in the interdomain packing are shown. The
coordinates are from the refined orthorhombic crystal form. (B)
Overlay of refined 2DL2 structures from the orthorhombic (in
green) and the trigonal (in blue) crystal forms.
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