Differences in structure and hibernation mechanism highlight diversification of the microsporidian ribosome.
Differences in structure and hibernation mechanism highlight diversification of the microsporidian ribosome.
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DOI：
10.1371/journal.pbio.3000958
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发表时间：
2020-10
期刊：
影响因子：
9.8
通讯作者：
Barandun J
中科院分区：
文献类型：
--
作者：
Ehrenbolger K;Jespersen N;Sharma H;Sokolova YY;Tokarev YS;Vossbrinck CR;Barandun J
组装和驱动核糖体是能源密集型过程，需要微调的细胞控制机制。在严格的营养限制下运行的生物体，如致病微孢子虫，通过核糖体冬眠和循环来保存能量是至关重要的。然而，微孢子虫冬眠的机制仍然知之甚少。在这里，我们展示了由保守的真核细胞冬眠和循环因子LSO2结合的蝗虫副孢子核糖体的冷冻电子显微镜结构。微孢子虫LSO2同源物采用V型构象连接mRNA解码位点和大亚基tRNA结合位点，提供了可逆的核糖体失活机制。虽然微孢子虫核糖体高度致密，但蝗虫微孢子虫核糖体保留了其他微孢子虫所没有的几个rRNA片段，并代表了rRNA还原的中间状态。在一种情况下，扩展片段的几乎完全减少导致了单个结合核苷酸，它可能作为稳定蛋白质-蛋白质界面的结构辅助因子。所呈现的结构突出了这些新出现的病原体的还原进化，并揭示了真核细胞核糖体冬眠的保守机制。微小致病真核生物微孢子虫进化出高度致密的核糖体，比细菌核糖体小，并利用各种冬眠因子来促进核糖体失活和从潜伏的孢子期恢复，包括保守的真核细胞冬眠和循环因子LSO2。
Assembling and powering ribosomes are energy-intensive processes requiring fine-tuned cellular control mechanisms. In organisms operating under strict nutrient limitations, such as pathogenic microsporidia, conservation of energy via ribosomal hibernation and recycling is critical. The mechanisms by which hibernation is achieved in microsporidia, however, remain poorly understood. Here, we present the cryo–electron microscopy structure of the ribosome from Paranosema locustae spores, bound by the conserved eukaryotic hibernation and recycling factor Lso2. The microsporidian Lso2 homolog adopts a V-shaped conformation to bridge the mRNA decoding site and the large subunit tRNA binding sites, providing a reversible ribosome inactivation mechanism. Although microsporidian ribosomes are highly compacted, the P. locustae ribosome retains several rRNA segments absent in other microsporidia, and represents an intermediate state of rRNA reduction. In one case, the near complete reduction of an expansion segment has resulted in a single bound nucleotide, which may act as an architectural co-factor to stabilize a protein–protein interface. The presented structure highlights the reductive evolution in these emerging pathogens and sheds light on a conserved mechanism for eukaryotic ribosome hibernation. Tiny pathogenic eukaryotes called microsporidia have evolved highly compact ribosomes, smaller than bacterial ribosomes, and employ diverse hibernation factors to facilitate ribosome inactivation and recovery from the latent spore stage, including the conserved eukaryotic hibernation and recycling factor Lso2.
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DOI：
10.1261/rna.056705.116
发表时间：
2016-08
期刊：
RNA (New York, N.Y.)
影响因子：
--
作者：
Ramesh M;Woolford JL Jr
通讯作者：
Woolford JL Jr
影响因子：
48
作者：
Punjani, Ali;Rubinstein, John L.;Brubaker, Marcus A.
通讯作者：
Brubaker, Marcus A.
影响因子：
5.6
作者：
Melnikov, Sergey V.;Manakongtreecheep, Kasidet;Soell, Dieter
通讯作者：
Soell, Dieter
影响因子：
28.3
作者：
Barandun, Jonas;Hunziker, Mirjam;Klinge, Sebastian
通讯作者：
Klinge, Sebastian
影响因子：
16
作者：
Fujii, Kotaro;Susanto, Teodorus Theo;Barna, Maria
通讯作者：
Barna, Maria