Secondary, tertiary, and quaternary structure of T-cell-specific immunoglobulin-like polypeptide chains.
Secondary, tertiary, and quaternary structure of T-cell-specific immunoglobulin-like polypeptide chains.
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DOI：
10.1073/pnas.83.3.742
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发表时间：
1986-02
影响因子：
11.1
通讯作者：
J. Novotný;S. Tonegawa;H. Saito;D. Kranz;H. Eisen
中科院分区：
文献类型：
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作者：
J. Novotný;S. Tonegawa;H. Saito;D. Kranz;H. Eisen
探讨B细胞和T细胞之间抗原识别的差异源于其各自抗原特异性受体的结构差异的可能性（B细胞上的免疫球蛋白和T细胞上的免疫球蛋白样分子），我们比较了T细胞受体α，β，以及γ多肽链和T细胞T8（Lyt-2）抗原链的N-末端区段与其三维结构已知的免疫球蛋白的相应区域。结果表明，四个T细胞多肽链被组织成免疫球蛋白样结构域，由多链反平行β折叠双层组成。在不同免疫球蛋白中保守的不变氨基酸侧链，包括介导结构域-结构域相互作用并形成抗体结合位点的恒定支架的那些，也在T细胞受体基因编码的链中和T8（Lyt-2）的N-末端结构域中保守。似乎抗原特异性T细胞α β链受体和抗体的结合位点在其总体尺寸和几何形状上非常相似：T细胞α β受体分子可能具有与抗体的常规结合位点基本上没有不同的抗原特异性结合位点。
To explore the possibility that the difference in antigen recognition between B and T cells derives from a structural difference in their respective antigen-specific receptors (immunoglobulins on B cells and immunoglobulin-like molecules on T cells), we compared the extracellular segments of the T-cell receptor alpha, beta, and gamma polypeptide chains and the N-terminal segment of the T-cell T8 (Lyt-2) antigen chain with the corresponding regions of immunoglobulins whose three-dimensional structures are known. The results indicate that the four T-cell polypeptide chains are organized into immunoglobulin-like domains consisting of multistranded antiparallel beta-sheet bilayers. Invariant amino acid side chains that are conserved in diverse immunoglobulins, including those that mediate domain-domain interactions and form a constant scaffold for antibody binding sites, are also conserved in the chains encoded by the T-cell receptor genes and in the N-terminal domain of T8 (Lyt-2). It appears that the binding sites of the antigen-specific T-cell alpha beta-chain receptors and of antibodies are very similar in their overall dimensions and geometry: a T-cell alpha beta receptor molecule probably has an antigen-specific binding site that is fundamentally no different than the conventional binding site of an antibody.