While a structural description of the molecular mechanisms guiding ribosome assembly in eukaryotic systems is emerging, bacteria employ an unrelated core set of assembly factors for which high-resolution structural information is still missing. Here we use solution state NMR to determine the apo structure of E. coli RimP and RbfA while single-particle cryo-EM is used to visualize the effect of the bacterial ribosome assembly factors RimP, RbfA, RsmA, and RsgA on the conformational landscape of the 30S subunit. This reveals a conserved rRNA switch in the 16S rRNA that initiates the folding of the decoding site on the 30S subunit and thus represents a critical coordination point in 30S biogenesis. Moreover, the high-resolution structural data reveals the molecular mechanisms employed by the assembly factors to coordinate and control the rRNA switch. Given rapidly emerging antibiotic resistance limiting antibiotic therapy, our results identify new key functional sites in 30S biogenesis that can be targeted for developing novel anti-infectives.

中文翻译：

---

保守的rRNA开关对于解码小核糖体亚基的位点成熟至关重要

虽然正在出现对真核系统中指导核糖体组装的分子机制的结构描述，但细菌采用了不相关的核心组装因子集，而高分辨率的结构信息仍缺乏。在这里，我们使用溶液状态NMR来确定大肠杆菌RimP和RbfA的载脂蛋白结构，同时使用单颗粒冷冻EM来可视化细菌核糖体装配因子RimP，RbfA，RsmA和RsgA对Apo构象的影响。 30S子单元 这揭示了16S rRNA中保守的rRNA开关，该开关启动了30S亚基上解码位点的折叠，因此代表了30S生物发生中的关键协调点。此外，高分辨率的结构数据揭示了装配因子用来协调和控制rRNA开关的分子机制。