Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg im Breisgau, Germany.
Infection Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland.
Angew Chem Int Ed Engl. 2022 May 23;61(22):e202201731. doi: 10.1002/anie.202201731. Epub 2022 Mar 30.
Magic Spot Nucleotides (MSN) regulate the stringent response, a highly conserved bacterial stress adaptation mechanism, enabling survival under adverse external challenges. In times of antibiotic crisis, a detailed understanding of stringent response is essential, as potentially new targets for pharmacological intervention could be identified. In this study, we delineate the MSN interactome in Escherichia coli and Salmonella typhimurium applying a family of trifunctional photoaffinity capture compounds. We introduce MSN probes covering a diverse phosphorylation pattern, such as pppGpp, ppGpp, and pGpp. Our chemical proteomics approach provides datasets of putative MSN receptors both from cytosolic and membrane fractions that unveil new MSN targets. We find that the activity of the non-Nudix hydrolase ApaH is potently inhibited by pppGpp, which itself is converted to pGpp by ApaH. The capture compounds described herein will be useful to identify MSN interactomes across bacterial species.
魔点核苷酸（MSN）调节严谨反应，这是一种高度保守的细菌应激适应机制，使细菌能够在不利的外部挑战下存活。在抗生素危机时期，深入了解严谨反应至关重要，因为可能会发现新的药理学干预靶点。在这项研究中，我们应用了一类三功能光亲和捕获化合物，描绘了大肠杆菌和鼠伤寒沙门氏菌中的 MSN 相互作用组。我们引入了覆盖多种磷酸化模式的 MSN 探针，如 pppGpp、ppGpp 和 pGpp。我们的化学蛋白质组学方法提供了来自细胞质和膜部分的假定 MSN 受体数据集，揭示了新的 MSN 靶标。我们发现，非 Nudix 水解酶 ApaH 的活性被 pppGpp 强烈抑制，而 pppGpp 本身又被 ApaH 转化为 pGpp。本文中描述的捕获化合物将有助于在不同的细菌物种中识别 MSN 相互作用组。
