3VQ1 image
Entry Detail
PDB ID:
3VQ1
Keywords:
Title:
Crystal structure of mouse TLR4/MD-2/lipid IVa complex
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2012-03-17
Release Date:
2012-05-09
Method Details:
Experimental Method:
Resolution:
2.70 Å
R-Value Free:
0.27
R-Value Work:
0.23
R-Value Observed:
0.23
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Toll-like receptor 4
Chain IDs:A, C (auth: B)
Chain Length:606
Number of Molecules:2
Biological Source:Mus musculus
Polymer Type:polypeptide(L)
Description:Lymphocyte antigen 96
Chain IDs:B (auth: C), D
Chain Length:144
Number of Molecules:2
Biological Source:Mus musculus
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
ASN A ASN GLYCOSYLATION SITE
Primary Citation
Structural basis of species-specific endotoxin sensing by innate immune receptor TLR4/MD-2
Proc.Natl.Acad.Sci.USA 109 7421 7426 (2012)
PMID: 22532668 DOI: 10.1073/pnas.1201193109

Abstact

Lipopolysaccharide (LPS), also known as endotoxin, activates the innate immune response through toll-like receptor 4 (TLR4) and its coreceptor, MD-2. MD-2 has a unique hydrophobic cavity that directly binds to lipid A, the active center of LPS. Tetraacylated lipid IVa, a synthetic lipid A precursor, acts as a weak agonist to mouse TLR4/MD-2, but as an antagonist to human TLR4/MD-2. However, it remains unclear as to how LPS and lipid IVa show agonistic or antagonistic activities in a species-specific manner. The present study reports the crystal structures of mouse TLR4/MD-2/LPS and TLR4/MD-2/lipid IVa complexes at 2.5 and 2.7 Å resolutions, respectively. Mouse TLR4/MD-2/LPS exhibited an agonistic "m"-shaped 2:2:2 complex similar to the human TLR4/MD-2/LPS complex. Mouse TLR4/MD-2/lipid IVa complex also showed an agonistic structural feature, exhibiting architecture similar to the 2:2:2 complex. Remarkably, lipid IVa in the mouse TLR4/MD-2 complex occupied nearly the same space as LPS, although lipid IVa lacked the two acyl chains. Human MD-2 binds lipid IVa in an antagonistic manner completely differently from the way mouse MD-2 does. Together, the results provide structural evidence of the agonistic property of lipid IVa on mouse TLR4/MD-2 and deepen understanding of the ligand binding and dimerization mechanism by the structurally diverse LPS variants.

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Primary Citation of related structures