Hassan Ahmed H, Pinkas Matyas, Yaeshima Chiaki, Ishino Sonoko, Uchiumi Toshio, Ito Kosuke, Demo Gabriel
Central European Institute of Technology, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.
Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Niigata 950-2181, Japan.
Nucleic Acids Res. 2025 Jan 11;53(2). doi: 10.1093/nar/gkae1324.
Protein synthesis (translation) consumes a substantial proportion of cellular resources, prompting specialized mechanisms to reduce translation under adverse conditions. Ribosome inactivation often involves ribosome-interacting proteins. In both bacteria and eukaryotes, various ribosome-interacting proteins facilitate ribosome dimerization or hibernation, and/or prevent ribosomal subunits from associating, enabling the organisms to adapt to stress. Despite extensive studies on bacteria and eukaryotes, understanding factor-mediated ribosome dimerization or anti-association in archaea remains elusive. Here, we present cryo-electron microscopy structures of an archaeal 30S dimer complexed with an archaeal ribosome dimerization factor (designated aRDF), from Pyrococcus furiosus, resolved at a resolution of 3.2 Å. The complex features two 30S subunits stabilized by aRDF homodimers in a unique head-to-body architecture, which differs from the disome architecture observed during hibernation in bacteria and eukaryotes. aRDF interacts directly with eS32 ribosomal protein, which is essential for subunit association. The binding mode of aRDF elucidates its anti-association properties, which prevent the assembly of archaeal 70S ribosomes.
蛋白质合成（翻译）消耗了细胞资源的很大一部分，促使细胞形成专门机制以在不利条件下减少翻译。核糖体失活通常涉及与核糖体相互作用的蛋白质。在细菌和真核生物中，多种与核糖体相互作用的蛋白质促进核糖体二聚化或休眠，和/或阻止核糖体亚基结合，使生物体能够适应压力。尽管对细菌和真核生物进行了广泛研究，但对古菌中因子介导的核糖体二聚化或反结合的了解仍然很少。在这里，我们展示了来自嗜热栖热菌的与古菌核糖体二聚化因子（命名为aRDF）复合的古菌30S二聚体的冷冻电子显微镜结构，分辨率为3.2埃。该复合物的特征是两个30S亚基由aRDF同型二聚体以独特的头对体结构稳定，这与在细菌和真核生物休眠期间观察到的双体结构不同。aRDF直接与核糖体蛋白eS32相互作用，而eS32对于亚基结合至关重要。aRDF的结合模式阐明了其反结合特性，该特性可阻止古菌70S核糖体的组装。
