This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
2d3v
From Proteopedia
| |||||||
| , resolution 1.85Å | |||||||
|---|---|---|---|---|---|---|---|
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal Structure of Leukocyte Ig-like Receptor A5 (LILRA5/LIR9/ILT11)
Overview
Human leukocyte Ig-like receptor B1 (LILRB1) and B2 (LILRB2) belong to "Group 1" receptors and recognize a broad range of major histocompatibility complex class I molecules (MHCIs). In contrast, "Group 2" receptors show low similarity with LILRB1/B2, and their ligands remain to be identified. To date, the structural and functional characteristics of Group 2 LILRs are poorly understood. Here we report the crystal structure of the extracellular domain of LILRA5, which is an activating Group 2 LILR expressed on monocytes and neutrophils. Unexpectedly, the structure showed large changes in structural conformation and charge distribution in the region corresponding to the MHCI binding site of LILRB1/B2, which are also distinct from killer cell Ig-like receptors and Fc alpha receptors. These changes probably confer the structural hindrance for the MHCI binding, and their key amino acid substitutions are well conserved in Group 2 LILRs. Consistently, the surface plasmon resonance and flow cytometric analyses demonstrated that LILRA5 exhibited no affinities to all tested MHCIs. These results raised the possibility that LILRA5 as well as Group 2 LILRs do not play a role in any MHCI recognition but could possibly bind to non-MHCI ligand(s) on the target cells to provide a novel immune regulation mechanism.
About this Structure
2D3V is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structure of the human monocyte-activating receptor, "Group 2" leukocyte Ig-like receptor A5 (LILRA5/LIR9/ILT11)., Shiroishi M, Kajikawa M, Kuroki K, Ose T, Kohda D, Maenaka K, J Biol Chem. 2006 Jul 14;281(28):19536-44. Epub 2006 May 3. PMID:16675463
Page seeded by OCA on Thu Mar 20 16:23:01 2008
