静电学在 siderophore 免疫蛋白 Siderocalin 的识别中的作用
Trisha M Hoette1, Rebecca J Abergel, Jide Xu
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|December 5, 2008
概括
西德罗卡林与细菌的 siderophores 结合,以阻止铁的吸收. 当 siderophores 缺乏结构不兼容性时,静电相互作用,而不是硬体碰撞,决定了结合强度.
科学领域:
- 生物化学 生物化学
- 免疫学 免疫学 免疫学
- 微生物学 微生物学
背景情况:
- 铁对细菌毒性至关重要,需要 siderophores 在宿主中获取铁.
- 西德罗卡林是一种人体蛋白质,它与 siderophores 结合,以抑制细菌的铁吸收和毒性.
- 立体碰撞和静电相互作用会影响Siderocalin的 siderophore 结合.
研究的目的:
- 解构静电相互作用对Siderocalin对 siderophore识别的贡献.
- 为了研究电荷-电荷和阴离子-pi相互作用在结合 2,3-catecholate siderophores 的作用.
- 了解 siderophore 结构的变化如何影响与 Siderocalin 的结合亲和力.
主要方法:
- 用不同的2,3-甲基胺 (CAM) 和N-基氨酸 (1,2-HOPO) 单位合成异性肠杆菌素类似物.
- 小分子晶体学以确定模拟物的形状互补性.
- 基于光的结合试验用于测量结合亲和力.
- 开始计算以建模静电特性.
主要成果:
- 所有合成的类似物都适合在Siderocalin的结合口袋中.
- 具有较少CAM单元的铁性 siderophore 复合体表现出明显较低的结合亲和力.
- 由于CAM单元数量下降,结合亲和力下降 (K (d) 值从>600 nM降至0.3 nM).
结论:
- 在没有固态碰撞的情况下,静电相互作用是 siderophore 与 Siderocalin 的结合强度的关键决定因素.
- 2,3-甲基胺基单元的数量与 siderophore 类型的结合亲和力直接相关.
- 这项研究阐明了Siderocalin对 siderophore 识别的基础的静电机制.
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