一个 gamma delta T 细胞受体连接体 T22 的晶体结构:一个截断的 MHC 类折叠
C Wingren1, M P Crowley, M Degano
1Department of Molecular Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
概括
鼠T10和T22,相关的非经典MHC Ib蛋白质,直接与马达尔塔T细胞受体结合. 结构分析揭示了一种不寻常的MHC类折叠,表明了明显的gammadelta和alphabeta T细胞受体相互作用.
科学领域:
- 免疫学 免疫学 免疫学
- 结构生物学 结构生物学
- 分子生物学分子生物学
背景情况:
- 非古典性主要基因相容性复合体 (MHC) Ib 蛋白质,如小鼠T10和T22,在结构上与经典的MHC I 类分子相似.
- 已知这些蛋白质与特定的 gamma delta T 细胞受体 (TCR) 相互作用,通常独立于结合.
研究的目的:
- 阐明T22b-TCR相互作用的结构基础.
- 研究T10和T22结构变异对马三角体TCR结合的功能影响.
- 为了比较马三角体TCR与MHC样分子的相互作用机制,与与经典MHC配体的alphabeta TCR相比.
主要方法:
- 采用X射线晶体学,确定T22b蛋白的高分辨率 (3.1安格斯特罗姆) 晶体结构.
- 使用点突变和T10和T22蛋白质的等位变异进行了功能映射.
- 对结构特征和功能数据进行了比较分析.
主要成果:
- T22b的晶体结构与MHC I类分子相似,但具有截断的酸结合槽,可以直接进入β-sheet地板.
- 功能映射确定了T10和T22上的潜在的gamma delta TCR结合点.
- T22表现出一种不寻常的MHC类折叠,与经典的MHC类I不同.
结论:
- T22代表了MHC类折叠的独特变体,对免疫识别有影响.
- 结构性发现表明,相比于alphabeta TCR与经典MHC连接体相互作用的方式,gammadelta TCR与其MHC连接体相互作用的方式不同.
- 这项研究提供了关于免疫系统内T细胞受体识别的多样化机制的见解.
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