Crystal structure of a superantigen bound to MHC class II displays zinc and peptide dependence.
The three-dimensional structure of a bacterial superantigen, Staphylococcus aureus enterotoxin H (SEH), bound to human major histocompatibility complex (MHC) class II (HLA-DR1) has been determined by X-ray crystallography to 2.6 A resolution (1HXY). The superantigen binds on top of HLA-DR1 in a completely different way from earlier co-crystallized superantigens from S.aureus. SEH interacts with high affinity through a zinc ion with the beta1 chain of HLA-DR1 and also with the peptide presented by HLA-DR1. The structure suggests that all superantigens interacting with MHC class II in a zinc-dependent manner present the superantigen in a common way. This suggests a new model for ternary complex formation with the T-cell receptor (TCR), in which a contact between the TCR and the MHC class II is unlikely.
Petersson
K
K
Molecular Biophysics, Centre for Chemistry and Chemical Engineering, Lund University, PO Box 124, S-221 00 Lund, Sweden.
Håkansson
M
M
Nilsson
H
H
Forsberg
G
G
Svensson
L A
LA
Liljas
A
A
Walse
B
B
D000595:Amino Acid Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray / Q000379:methods; D004768:Enterotoxins / Q000737:chemistry* / Q000276:immunology; D015798:HLA-DR1 Antigen / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus; D018089:Superantigens / Q000737:chemistry / Q000276:immunology; D015032:Zinc / Q000737:chemistry; D016335:Zinc Fingers
D004768:Enterotoxins; D015798:HLA-DR1 Antigen; D011994:Recombinant Proteins; C402489:Staphylococcal enterotoxin H; D018089:Superantigens; D015032:Zinc