外毒素A-eEF2复杂结构表明ADP通过核糖体仿真进行核糖化
René Jørgensen1, A Rod Merrill, Susan P Yates
1Centre for Structural Biology, Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000, Denmark.
Nature
|August 19, 2005
概括
像Pseudomonas aeruginosa外毒素A (ETA) 这样的细菌毒素通过ADP核糖化修改蛋白质. 延长因子2 (eEF2) 中的二胺残留物对于这种反应至关重要,与毒素和NAD+相互作用.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 许多致病细菌分泌出单一ADP-ribosylating毒素.
- 这些毒素会改变细胞内蛋白质,包括翻译延长因子2 (eEF2).
- 了解ADP核糖化机制是开发治疗方法的关键.
研究的目的:
- 为了阐明由 Pseudomonas aeruginosa exotoxin A (ETA) 的 ADP 核糖化过程的结构基础.
- 为了研究二胺残留在eEF2在酶反应期间的作用.
- 了解ETA对eEF2的普遍识别机制.
主要方法:
- 确定了ETA和eEF2.2之间的催化活性复合物的四个晶体结构.
- 使用一种不可水解的NAD+模拟物 (betaTAD) 来捕获反应中间体.
- 分析了ETA,eEF2和betaTAD之间的结构相互作用.
主要成果:
- 在eEF2中的二胺残留物跨越了裂,并与NAD+模拟物相互作用.
- 迪夫他胺似乎对触发NAD+裂变和稳定反应中间体至关重要.
- 结合的NAD+类似物模仿rRNA核酸,解释了ETA对eEF2.2的广泛识别.
结论:
- 双胺是ETA对ADP核糖化必不可少的,可能是通过促进NAD+裂变.
- 通过一个涉及rRNA结构模仿的机制,ETA识别eEF2.
- 这些发现可能有助于了解类似的毒素,如喉毒素.
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