肉毒神经毒素利用宿主消化蛋白酶通过激活OrfXs/P47来增加它们的口服毒性
Linfeng Gao1, Maria Barbara Nowakowska2, Katja Selby2
1Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA.
Nature structural & molecular biology
|January 21, 2025
概括
orfX基因集群组件 (OrfXs和P47) 增强了小鼠的肉毒神经毒素 (BoNT) 口服毒性. 对OrfX2的蛋白质分解激活及其与NTNH的结合对于这种增强的毒性至关重要.
科学领域:
- 微生物学 微生物学
- 毒理学 毒理学 毒理学
- 结构生物学 结构生物学
背景情况:
- 肉毒神经毒素 (BoNTs) 是由细菌产生的强毒素,通常与orfX基因集群有关.
- orfX集群编码了四种非毒性蛋白质 (OrfX1,OrfX2,OrfX3和P47),其功能以前是未知的.
- 这种基因集群也存在于产生口服杀虫毒素的细菌中.
研究的目的:
- 阐明OrfX1,OrfX2,OrfX3和P47在BoNT毒性方面的功能.
- 研究这些成分增强口服BoNT毒性的机制.
- 了解这些蛋白质和BoNT之间的相互作用的结构基础.
主要方法:
- 在小鼠体内口服毒性测定.
- 蛋白质溶解活性研究.
- 电子显微镜 (Cryo-EM) 用于结构分析.
- 生物化学测试用于研究蛋白质相互作用.
主要成果:
- OrfXs和P47的联合作用显著增加了BoNT在小鼠的口服毒性.
- 对于这种增强的毒性,需要通过消化蛋白酶激活蛋白质.
- 在蛋白酶激活状态下,OrfX2与无毒的非血凝素 (NTNH) 结合.
- 化EM揭示了一种特定的结合模式,其中两个激活的OrfX2分子与NTNH结合在一起,这对于提高口服BoNT毒性至关重要.
结论:
- OrfXs和P47在增强肉毒神经毒素的口服毒性方面发挥着至关重要的作用.
- 蛋白溶解激活是这些相关蛋白质功能的一个关键调节机制.
- 对OrfX2-NTNH相互作用的结构洞察力为了解毒素病原和开发对策提供了基础.
- 这些发现对理解携带同源orfX和P47基因的其他细菌毒素有意义.
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