Ribosomes are the macromolecular machines at the heart of protein synthesis, however, their function can be modulated by a variety of additional protein factors that directly interact with them. Here, we report the cryo-EM structure of human Ebp1 (p48 isoform) bound to the human 80S ribosome at 3.3 Å resolution. Ebp1 binds in the vicinity of the peptide exit tunnel on the 80S ribosome and this binding is enhanced upon puromycin-mediated translational inhibition. The association of Ebp1 with the 80S ribosome centers around its interaction with ribosomal proteins eL19 and uL23 and the 28S rRNA. Further analysis of the Ebp1¬-ribosome complex suggests that Ebp1 can rotate around its insert domain, which may enable it assume a wide range of conformations while maintaining its interaction with the ribosome. Structurally, Ebp1 shares homology with the methionine aminopeptidase 2 family of enzymes, therefore, this inherent flexibility may also be conserved.

中文翻译：

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人类 Ebp1 与核糖体的动态关联

核糖体是蛋白质合成核心的大分子机器，然而，它们的功能可以通过与它们直接相互作用的各种其他蛋白质因子进行调节。在这里，我们报告了以 3.3 Å 分辨率与人类 80S 核糖体结合的人类 Ebp1（p48 同种型）的冷冻电镜结构。Ebp1 结合在 80S 核糖体上的肽出口隧道附近，这种结合在嘌呤霉素介导的翻译抑制后得到增强。Ebp1 与 80S 核糖体的关联围绕其与核糖体蛋白 eL19 和 uL23 以及 28S rRNA 的相互作用。对 Ebp1-核糖体复合物的进一步分析表明，Ebp1 可以围绕其插入域旋转，这可能使其具有广泛的构象，同时保持与核糖体的相互作用。在结构上，