Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 6-mer - A4B1C1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 152.46 kDa 
• Atom Count: 9511 
• Modelled Residue Count: 1200 
• Deposited Residue Count: 1326 
• Unique protein chains: 2

1KTK

Complex of Streptococcal pyrogenic enterotoxin C (SpeC) with a human T cell receptor beta chain (Vbeta2.1)

• DOI: 10.2210/pdb1KTK/pdb

• Classification: IMMUNE SYSTEM
• Organism(s): Streptococcus pyogenes, Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2002-01-16 Released: 2002-06-07 
• Deposition Author(s): Sundberg, E.J., Li, H., Llera, A.S., McCormick, J.K., Tormo, J., Karjalainen, K., Schlievert, P.M., Mariuzza, R.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.00 Å
• R-Value Free: 0.334 
• R-Value Work: 0.326 
• R-Value Observed: 0.326 

Literature

Structures of two streptococcal superantigens bound to TCR beta chains reveal diversity in the architecture of T cell signaling complexes.

Sundberg, E.J., Li, H., Llera, A.S., McCormick, J.K., Tormo, J., Schlievert, P.M., Karjalainen, K., Mariuzza, R.A.

(2002) Structure 10: 687-699

• PubMed: 12015151 
• DOI: 10.1016/s0969-2126(02)00759-1
• Primary Citation of Related Structures:  
  1L0Y, 1L0X, 1KTK


• PubMed Abstract: 
  

Superantigens (SAGs) crosslink MHC class II and TCR molecules, resulting in an overstimulation of T cells associated with human disease. SAGs interact with several different surfaces on MHC molecules, necessitating the formation of multiple distinct MHC-SAG-TCR ternary signaling complexes. Variability in SAG-TCR binding modes could also contribute to the structural heterogeneity of SAG-dependent signaling complexes. We report crystal structures of the streptococcal SAGs SpeA and SpeC in complex with their corresponding TCR beta chain ligands that reveal distinct TCR binding modes. The SpeC-TCR beta chain complex structure, coupled with the recently determined SpeC-HLA-DR2a complex structure, provides a model for a novel T cell signaling complex that precludes direct TCR-MHC interactions. Thus, highly efficient T cell activation may be achieved through structurally diverse strategies of TCR ligation.

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Organizational Affiliation: 

Center for Advanced Research in Biotechnology, W.M. Keck Laboratory for Structural Biology, University of Maryland Biotechnology Institute, 9600 Gudelsky Drive, Rockville, MD 20850, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Exotoxin type C	A, B, C, D	208	Streptococcus pyogenes	Mutation(s): 0
Find proteins for Q8NKX2 (Streptococcus pyogenes serotype M18 (strain MGAS8232)) Explore Q8NKX2  Go to UniProtKB:  Q8NKX2

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
T-cell receptor beta chain	E, F	247	Homo sapiens	Mutation(s): 0  Gene Names: TRBC1
Find proteins for P01850 (Homo sapiens) Explore P01850  Go to UniProtKB:  P01850

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.00 Å
• R-Value Free: 0.334 
• R-Value Work: 0.326 
• R-Value Observed: 0.326 
• Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 57.378	α = 90
b = 146.764	β = 98.61
c = 135.69	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing
CNS	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2002-01-16 
• Released Date: 2002-06-07 
Deposition Author(s): Sundberg, E.J., Li, H., Llera, A.S., McCormick, J.K., Tormo, J., Karjalainen, K., Schlievert, P.M., Mariuzza, R.A.

Revision History  

• Version 1.0: 2002-06-07
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance