Plants being sessile organisms exhibit unique features in ribosomes, which might aid in rapid gene expression and regulation in response to varying environmental conditions. Here, we present high-resolution structures of the 60S and 80S ribosomes from wheat, a monocot staple crop plant (). While plant ribosomes have unique plant-specific rRNA modification (Cm1847) in the peptide exit tunnel (PET), the zinc-finger motif in eL34 is absent, and uL4 is extended, making an exclusive interaction network. We note differences in the eL15-helix 11 (25S) interaction, eL6-ES7 assembly, and certain rRNA chemical modifications between monocot and dicot ribosomes. In eukaryotes, we observe highly conserved rRNA modification (Gm75) in 5.8S rRNA and a flipped base (G1506) in PET. These features are likely involved in sensing or stabilizing nascent chain. Finally, we discuss the importance of the universal conservation of three consecutive rRNA modifications in all ribosomes for their interaction with A-site aminoacyl-tRNA.

中文翻译：

---

小麦核糖体的冷冻电镜结构揭示了植物核糖体的独特特征

作为无柄生物的植物在核糖体中表现出独特的特征，这可能有助于快速基因表达和调节以响应不同的环境条件。在这里，我们展示了来自小麦（一种单子叶作物）的 60S 和 80S 核糖体的高分辨率结构。虽然植物核糖体在肽出口隧道 (PET) 中具有独特的植物特异性 rRNA 修饰 (Cm1847)，但 eL34 中的锌指基序不存在，并且 uL4 被扩展，形成了独特的相互作用网络。我们注意到单子叶植物和双子叶植物核糖体之间 eL15-螺旋 11 (25S) 相互作用、eL6-ES7 组装以及某些 rRNA 化学修饰的差异。在真核生物中，我们观察到 5.8S rRNA 中高度保守的 rRNA 修饰 (Gm75) 和 PET 中的翻转碱基 (G1506)。这些特征可能涉及传感或稳定新生链。最后，我们讨论了所有核糖体中三个连续 rRNA 修饰的普遍保守性对于它们与 A 位氨酰基-tRNA 相互作用的重要性。