Department of Chemistry , Indian Institute of Technology Bombay , Powai, Mumbai 400076 , India.
J Am Chem Soc. 2019 Jan 30;141(4):1425-1429. doi: 10.1021/jacs.8b10277. Epub 2019 Jan 16.
Post-translational methylation of rRNA at select positions is a prevalent resistance mechanism adopted by pathogens. In this work, KsgA, a housekeeping ribosomal methyltransferase (rMtase) involved in ribosome biogenesis, was exploited as a model system to delineate the specific targeting determinants that impart substrate specificity to rMtases. With a combination of evolutionary and structure-guided approaches, a set of chimeras were created that altered the targeting specificity of KsgA such that it acted similarly to erythromycin-resistant methyltransferases (Erms), rMtases found in multidrug-resistant pathogens. The results revealed that specific loop embellishments on the basic Rossmann fold are key determinants in the selection of the cognate RNA. Moreover, in vivo studies confirmed that chimeric constructs are competent in imparting macrolide resistance. This work explores the factors that govern the emergence of resistance and paves the way for the design of specific inhibitors useful in reversing antibiotic resistance.
rRNA 翻译后在特定位置的甲基化是病原体普遍采用的一种耐药机制。在这项工作中，KsgA（一种参与核糖体生物发生的看家核糖体甲基转移酶（rMtase））被用作模型系统，以描绘赋予 rMtase 底物特异性的特定靶向决定因素。通过进化和结构导向方法的结合，创建了一组嵌合体，改变了 KsgA 的靶向特异性，使其类似于红霉素抗性甲基转移酶（Erms），即多药耐药病原体中发现的 rMtase。结果表明，基本 Rossmann 折叠上的特定环修饰是选择同源 RNA 的关键决定因素。此外，体内研究证实，嵌合构建体能够赋予大环内酯类药物抗性。这项工作探讨了控制耐药性出现的因素，并为设计有用的逆转抗生素耐药性的特异性抑制剂铺平了道路。
