对Ig超级家族的补充受体的新见解来自两种突变体的结构和功能研究
Huiquan Duan1, Troy G Abram1, Ana Rita Cruz2
1Department of Biochemistry and Molecular Biophysics, Kansas State University; Manhattan, KS.
ImmunoHorizons
|November 30, 2023
概括
补充Ig超级家族的补充受体 (CRIg) 结合了补充C3片段,并抑制了替代途径. 突变者表现出较低的亲和力,但可以被设计为增强的抑制功能.
科学领域:
- 免疫学 免疫学 免疫学
- 补充系统生物学 补充系统生物学
背景情况:
- 已知Ig超级家族的补充受体 (CRIg) 结合C3裂变产物并抑制补充的替代途径 (AP).
- 了解CRIg的结合 afinities 和抑制机制对于治疗开发至关重要.
研究的目的:
- 调查野生型CRIg和新型 lysine-deficient突变体的结合特性和抑制潜力.
- 通过化学修饰探索增强CRIg抑制功能的方法.
主要方法:
- 两种缺乏多重氨酸残留物的CRIg突变的生成和结构分析.
- 使用生物化学测试确定与C3b,iC3b和C3c的结合亲缘关系.
- 流细胞计测试,以评估结合对色化黄金葡萄球菌的结合.
- 使用红细胞溶解试验测量替代途径抑制.
- 一个CRIg突变体的化学修饰 (氨基胺反应交联)
主要成果:
- 野生类型的CRIg对C3b和iC3b有很高的亲和力 (<100nM),对C3c有较低的亲和力 (~1μM).
- 与野生类型相比,CRIg突变体的结合亲和力和细菌细胞结合量减少了2到3倍.
- 这两种突变都显示出替代途径抑制功效减少了约3倍.
- 一个单氨酸CRIg突变体的氨基反应性交叉连接显著提高了其抑制功效,以交叉连接器长度依赖的方式.
结论:
- 氨酸残留物对于最佳的CRIg结合亲和力和替代途径抑制很重要.
- 化学修饰,特别是交叉链接,提供了一种可行的策略,用于设计更强大的基于CRIg的替代途径抑制剂.
- 这些发现为开发针对补充系统的新疗法提供了基础.
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