C1-IgG1的结构提供了关于危险模式识别如何激活补充的见解
Deniz Ugurlar1, Stuart C Howes2, Bart-Jan de Kreuk3
1Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands.
概括
这项研究揭示了C1复合体如何通过与抗体结合来启动补充级联. 低温电子显微镜显示在抗体结合时C1q臂的凝聚和蛋白质酶的重新排列,澄清了免疫反应触发因素.
科学领域:
- 免疫学
- 结构生物学
- 生物化学
背景情况:
- 补充级联对于先天免疫和病原体清除至关重要.
- 由微生物或宿主细胞损伤模式触发C1复合体的补充级联.
- 对于C1的补充启动的确切机制尚不完全理解.
研究的目的:
- 阐明C1复合体启动补充级联的结构机制.
- 研究C1与抗体,特别是免疫球蛋白G1 (IgG1) 之间的相互作用.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 分析与单克隆抗体结合的C1复合结构.
- 用IgG1突变的功能分析来验证观察到的相互作用.
主要成果:
- 观察到单个和集群的C1-IgG1六合体结构.
- 在IgG1 Fc- CH2域上确定了C1q的特定结合位,包括新的相互作用.
- 抗体结合导致C1q臂凝结,C1r2s2蛋白酶的重新排列,以及C1q茎的倾斜.
- 数据表明C1s的C1r激活可以发生在单张C1复合体内或相邻复合体之间.
结论:
- 抗体与C1结合会诱导形状变化,可能导致补充级联启动.
- 这些发现为了解C1激活如何发生在表面提供了结构基础.
- 这项研究阐明了通过经典补充途径激活先天免疫反应的关键步骤.
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