核酸和金属化物驱动的构造变化在酸盐流量ATPase ArsAA中发生
Shivansh Mahajan1, Ashley E Pall2, Yancheng E Li1
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125.
概括
化物 (AsIII) 的毒性是由ArsA ATPase控制的,ArsA ATPase经历着形状变化来结合和运输有毒金属质. 这项研究揭示了ArsAA.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 微生物学 微生物学
背景情况:
- 化物 (AsIII) 是一种有毒的金属化物,易于与细胞的硫醇结合,需要有机体的排毒机制.
- Prokaryotic arsenite 耐药性通常涉及 *ars* 操作子,细胞质 ATPase ArsA 在封存和输出 AsIII 中发挥着关键作用.
- 通过ArsA调节核酸解的AsIII结合和运输的精确机制仍然不完全理解.
研究的目的:
- 阐明在矿抗性路径中ArsA ATPase的分子机制.
- 描述ArsA在其催化循环期间以及对化物结合的反应中的构造变化.
- 为了提供一个结构基础,通过化物对ArsA的全激活.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定ArsA在各种核酸结合状态 (MgADP,MgATP) 和与酸盐复合的结构.
- 采用X射线吸收光谱 (XAS) 来确认ArsA.A.内的矿的协调状态和结合环境.
- 进行了生物化学测试,以描述ArsA的功能性质及其相互作用.
主要成果:
- 冷-EM结构揭示了不同的开放MgADP结合和MgATP结合状态,以及与AsIII复合的封闭MgATP结合状态.
- XAS证实了AsIII的三坐标结合在封闭状态下保存的囊残留物.
- 这些结构显示了ArsA催化循环中的关键构造变化,与内 Walker A (IWA) ATPase家族一致,并揭示了AsIII介导的全激活的结构基础.
结论:
- ArsA的核酸状态决定了它的构造,暂时形成一个高亲和度的酸盐封存部位.
- 化结合以全性方式激活核酸水解,促进化向ArsB排泄的输送.
- 这项研究提供了通过ArsA ATPase调解的化物运输的详细结构和机制理解.
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