2gw5: Difference between revisions
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'''Crystal Structure of LIR-2 (ILT4) at 1.8 : differences from LIR-1 (ILT2) in regions implicated in the binding of the Cytomegalovirus class I MHC homolog UL18''' | {{Structure | ||
|PDB= 2gw5 |SIZE=350|CAPTION= <scene name='initialview01'>2gw5</scene>, resolution 1.80Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=IPA:ISOPROPYL ALCOHOL'>IPA</scene> | |||
|ACTIVITY= | |||
|GENE= LILRB2 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]) | |||
}} | |||
'''Crystal Structure of LIR-2 (ILT4) at 1.8 : differences from LIR-1 (ILT2) in regions implicated in the binding of the Cytomegalovirus class I MHC homolog UL18''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
2GW5 is a [ | 2GW5 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GW5 OCA]. | ||
==Reference== | ==Reference== | ||
Crystal structure of LIR-2 (ILT4) at 1.8 A: differences from LIR-1 (ILT2) in regions implicated in the binding of the Human Cytomegalovirus class I MHC homolog UL18., Willcox BE, Thomas LM, Chapman TL, Heikema AP, West AP Jr, Bjorkman PJ, BMC Struct Biol. 2002 Oct 11;2:6. PMID:[http:// | Crystal structure of LIR-2 (ILT4) at 1.8 A: differences from LIR-1 (ILT2) in regions implicated in the binding of the Human Cytomegalovirus class I MHC homolog UL18., Willcox BE, Thomas LM, Chapman TL, Heikema AP, West AP Jr, Bjorkman PJ, BMC Struct Biol. 2002 Oct 11;2:6. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/12390682 12390682] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: Willcox, B E.]] | [[Category: Willcox, B E.]] | ||
[[Category: IPA]] | [[Category: IPA]] | ||
[[Category: ig like | [[Category: ig like domain]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 17:09:53 2008'' | ||
Revision as of 18:09, 20 March 2008
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| , resolution 1.80Å | |||||||
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| Ligands: | |||||||
| Gene: | LILRB2 (Homo sapiens) | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal Structure of LIR-2 (ILT4) at 1.8 : differences from LIR-1 (ILT2) in regions implicated in the binding of the Cytomegalovirus class I MHC homolog UL18
OverviewOverview
BACKGROUND: Leukocyte Immunoglobulin-like Receptor-1 (LIR-1) and LIR-2 (also known as ILT2 and ILT4 respectively) are highly related cell surface receptors that bind a broad range of class I MHC molecules with low (microM) affinities. Expressed on monocytic cells and macrophages, both molecules transmit inhibitory signals after binding ligands. In addition to binding host class I MHC, the LIR-1 molecule, which is also expressed on lymphoid tissues, binds with a high (nM) affinity to UL18, a class I MHC homolog encoded by Human Cytomegalovirus (HCMV). In comparison, LIR-2 binds UL18 only weakly (microM KD). To understand how HCMV preferentially targets the more broadly expressed LIR-1 molecule, we determined the crystal structure of a ligand-binding fragment of LIR-2, and compared this to the existing high-resolution crystal structure of LIR-1. RESULTS: Recombinant LIR-2 (domains 1 and 2) was produced in E. coli and crystallized using streak seeding to optimize the crystal morphology. A data set complete to 1.8 A was collected at 100 K from a single crystal in the P4(1)2(1)2 spacegroup. The structure was solved by molecular replacement, using a search model based on the LIR-1 structure. CONCLUSIONS: The overall structure of LIR-2 D1D2 resembles both LIR-1, and Killer Inhibitory Receptors, in that the A strand in each domain forms hydrogen bonds to both beta sheets, and there is a sharp angle between the two immunoglobulin-like domains. However, differences from LIR-1 are observed in each domain, with two key changes apparent in the ligand-binding domain, D1. The region corresponding to the residue 44-57 helix of LIR-1 adopts a topology distinct from that of both LIR-1 and the KIR structures, involving a shortened 310 helix. Secondly, the predicted UL18 binding region of LIR-1 is altered substantially in LIR-2: the 76-84 loop mainchain is displaced 11 A with respect to LIR-1, and Tyrosine 38 adopts an alternative rotamer conformation. In summary, the structure of LIR-2 has revealed significant differences to LIR-1, including ones that may help to explain the >1000-fold lower affinity of LIR-2 for UL18.
About this StructureAbout this Structure
2GW5 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of LIR-2 (ILT4) at 1.8 A: differences from LIR-1 (ILT2) in regions implicated in the binding of the Human Cytomegalovirus class I MHC homolog UL18., Willcox BE, Thomas LM, Chapman TL, Heikema AP, West AP Jr, Bjorkman PJ, BMC Struct Biol. 2002 Oct 11;2:6. PMID:12390682
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