 |
PDBsum entry 4nfc
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Immune system
|
PDB id
|
|
|
|
4nfc
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Pilrα and pilrβ have a siglec fold and provide the basis of binding to sialic acid.
|
|
|
Authors
|
|
Q.Lu,
G.Lu,
J.Qi,
H.Wang,
Y.Xuan,
Q.Wang,
Y.Li,
Y.Zhang,
C.Zheng,
Z.Fan,
J.Yan,
G.F.Gao.
|
|
|
Ref.
|
|
Proc Natl Acad Sci U S A, 2014,
111,
8221-8226.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
Paired immunoglobulin-like type 2 receptor α (PILRα) and β (PILRβ) belong to
the PILR family and are related to innate immune regulation in various species.
Despite their high sequence identity, PILRα and PILRβ are shown to have
variant sialic acid (SA) binding avidities. To explore the molecular basis of
this interaction, we solved the crystal structures of PILRα and PILRβ at
resolutions of 1.6 Å and 2.2 Å, respectively. Both molecules adopt a typical
siglec fold but use a hydrophobic bond to substitute the siglec-specific
disulfide linkage for protein stabilization. We further used HSV-1 glycoprotein
B (gB) as a representative molecule to study the PILR-SA interaction. Deploying
site-directed mutagenesis, we demonstrated that three residues (Y2, R95, and
W108) presented on the surface of PILRα form the SA binding site equivalent to
those in siglecs but are arranged in a unique linear mode. PILRβ differs from
PILRα in one of these three residues (L108), explaining its inability to engage
gB. Mutation of L108 to tryptophan in PILRβ restored the gB-binding capacity.
We further solved the structure of this PILRβ mutant complexed with SA, which
reveals the atomic details mediating PILR/SA recognition. In comparison with the
free PILR structures, amino acid Y2 oriented variantly in the complex structure,
thereby disrupting the linear arrangement of PILR residues Y2, R95, and W108. In
conclusion, our study provides significant implications for the PILR-SA
interaction and paves the way for understanding PILR-related ligand binding.
|
|
|
|
|
|
|
