6CUG image
Entry Detail
PDB ID:
6CUG
Keywords:
Title:
Crystal structure of BC8B TCR-CD1b-PC complex
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2018-03-26
Release Date:
2019-01-16
Method Details:
Experimental Method:
Resolution:
2.40 Å
R-Value Free:
0.22
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:T-cell surface glycoprotein CD1b
Chain IDs:A
Chain Length:300
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Beta-2-microglobulin
Chain IDs:B
Chain Length:99
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:T-cell receptor alpha variable TRAV9-2 - BC8B TCR
Chain IDs:C (auth: D)
Chain Length:207
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:T-cell receptor beta variable TRBV6-2 - BC8B TCR
Chain IDs:D (auth: E)
Chain Length:245
Number of Molecules:1
Biological Source:Homo sapiens
Primary Citation
A T-cell receptor escape channel allows broad T-cell response to CD1b and membrane phospholipids.
Nat Commun 10 56 56 (2019)
PMID: 30610190 DOI: 10.1038/s41467-018-07898-0

Abstact

CD1 proteins are expressed on dendritic cells, where they display lipid antigens to T-cell receptors (TCRs). Here we describe T-cell autoreactivity towards ubiquitous human membrane phospholipids presented by CD1b. These T-cells discriminate between two major types of lipids, sphingolipids and phospholipids, but were broadly cross-reactive towards diverse phospholipids including phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine. The crystal structure of a representative TCR bound to CD1b-phosphatidylcholine provides a molecular mechanism for this promiscuous recognition. We observe a lateral escape channel in the TCR, which shunted phospholipid head groups sideways along the CD1b-TCR interface, without contacting the TCR. Instead the TCR recognition site involved the neck region phosphate that is common to all major self-phospholipids but absent in sphingolipids. Whereas prior studies have focused on foreign lipids or rare self-lipids, we define a new molecular mechanism of promiscuous recognition of common self-phospholipids including those that are known targets in human autoimmune disease.

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Primary Citation of related structures