保存的Arg-Asp对对在结石风神经毒素的结构和功能中的作用
Elizabeth A Wilson1, Ashtyn N Bevans1, Michael R Baldwin1
1Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA.
Toxins
|June 25, 2025
概括
结核病神经毒素 (TeNT) 使用其HCT域进行膜插入. 关键残留物的突变,如阿斯巴酸821改变pH取决于膜相互作用和毒素活性.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 神经科学是一个神经科学.
背景情况:
- 结核病神经毒素 (TeNT) 通过抑制神经传递引起.
- TeNT的HCT域介导pH触发的膜插入,以传递光链 (LC).
- 通过HCT介导的膜插入的精确机制在很大程度上是未知的.
研究的目的:
- 阐明HCT域介导膜插入的机制.
- 研究特定残留物 (R711,D821,W715) 在HCT功能和毒素活性中的作用.
- 了解受体结合域对LC转位的影响.
主要方法:
- 基于晶体结构的HCT域内保存的极性相互作用的分析.
- 在HCT变体中关键残留物 (R711,D821,W715) 的位点定向突变发生.
- 热稳定性测试,ANS结合研究和脂质体透性测试.
- 在皮层神经元中使用突变毒素对VAMP 2进行体外裂解测定.
主要成果:
- 在bHCT中Asp-Arg对的破坏改变了热稳定性,但没有影响二级结构.
- 与野生型bHCT相比,R711或D821的突变在更高的pH值下增加了膜相互作用.
- D821N突变增强了神经元中的VAMP 2裂变,表明LC转位独立于受体结合域.
- W715突变对HCT或全毒素活性的影响很小.
结论:
- 在低pH下D821的质子化破坏了与R711和W715的相互作用,导致HCT在膜插入方面发生了形状变化.
- 受体结合域影响膜插入的pH值,但对于LC转位并不重要.
- 在HCT域内的特定残留物在pH依赖的膜结合和毒素传递中起着关键作用.
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