Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 45.19 kDa 
• Atom Count: 3497 
• Residue Count: 387 
• Unique protein chains: 3

5T6Y

HLA-B*57:01 presenting TSTFEDVKILAF

• DOI: 10.2210/pdb5T6Y/pdb

• Classification: IMMUNE SYSTEM
• Organism(s): Homo sapiens, synthetic construct
• Expression System: Escherichia coli BL21
• Mutation(s): No 


• Deposited: 2016-09-02 Released: 2017-03-01 
• Deposition Author(s): Pymm, P., Rossjohn, J., Vivian, J.P.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.76 Å
• R-Value Free: 0.219 
• R-Value Work: 0.178 
• R-Value Observed: 0.180 

Literature

MHC-I peptides get out of the groove and enable a novel mechanism of HIV-1 escape.

Pymm, P., Illing, P.T., Ramarathinam, S.H., O'Connor, G.M., Hughes, V.A., Hitchen, C., Price, D.A., Ho, B.K., McVicar, D.W., Brooks, A.G., Purcell, A.W., Rossjohn, J., Vivian, J.P.

(2017) Nat Struct Mol Biol 24: 387-394

• PubMed: 28218747 
• DOI: 10.1038/nsmb.3381
• Primary Citation of Related Structures:  
  5T70, 5T6X, 5T6W, 5T6Z, 5T6Y


• PubMed Abstract: 
  

Major histocompatibility complex class I (MHC-I) molecules play a crucial role in immunity by capturing peptides for presentation to T cells and natural killer (NK) cells. The peptide termini are tethered within the MHC-I antigen-binding groove, but it is unknown whether other presentation modes occur. Here we show that 20% of the HLA-B*57:01 peptide repertoire comprises N-terminally extended sets characterized by a common motif at position 1 (P1) to P2. Structures of HLA-B*57:01 presenting N-terminally extended peptides, including the immunodominant HIV-1 Gag epitope TW10 (TSTLQEQIGW), showed that the N terminus protrudes from the peptide-binding groove. The common escape mutant TSNLQEQIGW bound HLA-B*57:01 canonically, adopting a dramatically different conformation than the TW10 peptide. This affected recognition by killer cell immunoglobulin-like receptor (KIR) 3DL1 expressed on NK cells. We thus define a previously uncharacterized feature of the human leukocyte antigen class I (HLA-I) immunopeptidome that has implications for viral immune escape. We further suggest that recognition of the HLA-B*57:01-TW10 epitope is governed by a 'molecular tension' between the adaptive and innate immune systems.

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Organizational Affiliation: 

Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria, Australia.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
HLA class I histocompatibility antigen, B-57 alpha chain	A	276	Homo sapiens	Mutation(s): 0  Gene Names: HLA-B, HLAB
Find proteins for P01889 (Homo sapiens) Explore P01889  Go to UniProtKB:  P01889
NIH Common Fund Data Resources
PHAROS  P01889 GTEx  ENSG00000234745

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Beta-2-microglobulin	B	99	Homo sapiens	Mutation(s): 0  Gene Names: B2M, CDABP0092, HDCMA22P
Find proteins for P61769 (Homo sapiens) Explore P61769  Go to UniProtKB:  P61769
NIH Common Fund Data Resources
PHAROS  P61769 GTEx  ENSG00000166710

Entity ID: 3
Molecule	Chains	Sequence Length	Organism	Details	Image
Decapeptide: THR-SER-THR-PHE-GLU-ASP-VAL-LYS-ILE-LEU-ALA-PHE	C	12	synthetic construct	Mutation(s): 0
Find proteins for Q6YHU6 (Homo sapiens) Explore Q6YHU6  Go to UniProtKB:  Q6YHU6
NIH Common Fund Data Resources
PHAROS  Q6YHU6 GTEx  ENSG00000115970

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
GOL	A, B	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N
ACT	A	ACETATE ION C2 H3 O2 QTBSBXVTEAMEQO-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.76 Å
• R-Value Free: 0.219 
• R-Value Work: 0.178 
• R-Value Observed: 0.180 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 50.707	α = 90
b = 82.043	β = 90
c = 110.095	γ = 90

Software Package:

Software Name	Purpose
PHENIX	refinement
MOSFLM	data reduction
SCALA	data scaling
PHASER	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2016-09-02 
• Released Date: 2017-03-01 
Deposition Author(s): Pymm, P., Rossjohn, J., Vivian, J.P.

Revision History 

• Version 1.0: 2017-03-01
  Type: Initial release
  
• Version 1.1: 2017-04-19
  Changes: Database references
• Version 1.2: 2017-08-09
  Changes: Data collection, Structure summary