Petersson K, Håkansson M, Nilsson H, Forsberg G, Svensson L A, Liljas A, Walse B
Molecular Biophysics, Centre for Chemistry and Chemical Engineering, Lund University, PO Box 124, S-221 00 Lund, Sweden.
EMBO J. 2001 Jul 2;20(13):3306-12. doi: 10.1093/emboj/20.13.3306.
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.
通过X射线晶体学已确定与人类主要组织相容性复合体(MHC)II类(HLA - DR1)结合的细菌超抗原金黄色葡萄球菌肠毒素H(SEH)的三维结构,分辨率达到2.6埃(1HXY)。该超抗原与HLA - DR1的结合方式与早期来自金黄色葡萄球菌的共结晶超抗原完全不同。SEH通过锌离子与HLA - DR1的β1链以及HLA - DR1呈递的肽以高亲和力相互作用。该结构表明,所有以锌依赖性方式与MHC II类相互作用的超抗原都以一种共同的方式呈递超抗原。这提示了一种与T细胞受体(TCR)形成三元复合物的新模型,其中TCR与MHC II类之间不太可能发生接触。