PDBsum entry 1b6u

Killer cell inhibitory receptor

PDB id: 1b6u

Contents

Protein chain

199 a.a. *

* Residue conservation analysis

PDB id:

1b6u

Name:

Killer cell inhibitory receptor

Title:

Crystal structure of the human killer cell inhibitory receptor (kir2dl3) specific for hla-cw3 related alleles

Structure:

P58 killer cell inhibitory receptor. Chain: a. Fragment: extracellular region. Synonym: kir2dl3. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Cell_line: bl21. Cell: natural killer cell. Cellular_location: cell surface. Gene: nkat2. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Monomer (from PDB file)

Resolution:

3.00Å R-factor: 0.248 R-free: 0.320

Authors:

K.Maenaka,T.Juji,D.I.Stuart,E.Y.Jones

Key ref:

K.Maenaka et al. (1999). Crystal structure of the human p58 killer cell inhibitory receptor (KIR2DL3) specific for HLA-Cw3-related MHC class I. Structure, 7, 391-398. PubMed id: 10196125 DOI: 10.1016/S0969-2126(99)80052-5

Date:

18-Jan-99 Release date: 27-Jan-99

Protein chain

P43628  (KI2L3_HUMAN) -  Killer cell immunoglobulin-like receptor 2DL3 from Homo sapiens

Seq: 341 a.a.

Struc: 199 a.a.

DOI no: 10.1016/S0969-2126(99)80052-5

Structure 7:391-398 (1999)

PubMed id: 10196125

Crystal structure of the human p58 killer cell inhibitory receptor (KIR2DL3) specific for HLA-Cw3-related MHC class I.

K.Maenaka, T.Juji, D.I.Stuart, E.Y.Jones.

ABSTRACT

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.

Selected figure(s)

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).

The above figure is reprinted by permission from Cell Press: Structure (1999, 7, 391-398) copyright 1999.

Figure was selected by an automated process.