3VJ6

Structure of the MHC class Ib molecule Qa-1b


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.201 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

A structural basis for antigen presentation by the MHC class Ib molecule, Qa-1b

Zeng, L.Sullivan, L.C.Vivian, J.P.Walpole, N.G.Harpur, C.M.Rossjohn, J.Clements, C.S.Brooks, A.G.

(2012) J.Immunol. 188: 302-310

  • DOI: 10.4049/jimmunol.1102379

  • PubMed Abstract: 
  • The primary function of the monomorphic MHC class Ib molecule Qa-1(b) is to present peptides derived from the leader sequences of other MHC class I molecules for recognition by the CD94-NKG2 receptors expressed by NK and T cells. Whereas the mode of ...

    The primary function of the monomorphic MHC class Ib molecule Qa-1(b) is to present peptides derived from the leader sequences of other MHC class I molecules for recognition by the CD94-NKG2 receptors expressed by NK and T cells. Whereas the mode of peptide presentation by its ortholog HLA-E, and subsequent recognition by CD94-NKG2A, is known, the molecular basis of Qa-1(b) function is unclear. We have assessed the interaction between Qa-1(b) and CD94-NKG2A and shown that they interact with an affinity of 17 μM. Furthermore, we have determined the structure of Qa-1(b) bound to the leader sequence peptide, Qdm (AMAPRTLLL), to a resolution of 1.9 Å and compared it with that of HLA-E. The crystal structure provided a basis for understanding the restricted peptide repertoire of Qa-1(b). Whereas the Qa-1(b-AMAPRTLLL) complex was similar to that of HLA-E, significant sequence and structural differences were observed between the respective Ag-binding clefts. However, the conformation of the Qdm peptide bound by Qa-1(b) was very similar to that of peptide bound to HLA-E. Although a number of conserved innate receptors can recognize heterologous ligands from other species, the structural differences between Qa-1(b) and HLA-E manifested in CD94-NKG2A ligand recognition being species specific despite similarities in peptide sequence and conformation. Collectively, our data illustrate the structural homology between Qa-1(b) and HLA-E and provide a structural basis for understanding peptide repertoire selection and the specificity of the interaction of Qa-1(b) with CD94-NKG2 receptors.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
H-2 class I histocompatibility antigen, D-37 alpha chain
A
277Mus musculusMutation(s): 0 
Gene Names: H2-T23
Find proteins for P06339 (Mus musculus)
Go to UniProtKB:  P06339
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Beta-2-microglobulin
B
100Mus musculusMutation(s): 0 
Gene Names: B2m
Find proteins for P01887 (Mus musculus)
Go to UniProtKB:  P01887
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Qdm peptide
P
9Mus musculusMutation(s): 0 
Gene Names: H2-L
Find proteins for P01897 (Mus musculus)
Go to UniProtKB:  P01897
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NI
Query on NI

Download SDF File 
Download CCD File 
A, B
NICKEL (II) ION
Ni
VEQPNABPJHWNSG-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.201 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 59.268α = 90.00
b = 72.833β = 90.00
c = 95.844γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
PHENIXrefinement
SCALEPACKdata scaling
PHASERphasing
CrystalCleardata collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-03-14
    Type: Initial release