Pellowe Grant A, Voisin Tomas B, Karpauskaite Laura, Maslen Sarah L, Roeselová Alžběta, Skehel J Mark, Roustan Chloe, George Roger, Nans Andrea, Kjær Svend, Taylor Ian A, Balchin David
Protein Biogenesis Laboratory, The Francis Crick Institute, London, UK.
Aston Institute for Membrane Excellence, Aston University, Birmingham, UK.
Nat Struct Mol Biol. 2025 Sep 19. doi: 10.1038/s41594-025-01676-5.
Proteins with multiple domains are intrinsically prone to misfold, yet fold efficiently during their synthesis on the ribosome. This is especially important in eukaryotes, where multidomain proteins predominate. Here we sought to understand how multidomain protein folding is modulated by the eukaryotic ribosome. We used hydrogen-deuterium exchange mass spectrometry and cryo-electron microscopy to characterize the structure and dynamics of partially synthesized intermediates of a model multidomain protein. We find that nascent subdomains fold progressively during synthesis on the human ribosome, templated by interactions across domain interfaces. The conformational ensemble of the nascent chain is tuned by its unstructured C-terminal segments, which keep interfaces between folded domains in dynamic equilibrium until translation termination. This contrasts with the bacterial ribosome, on which domain interfaces form early and remain stable during synthesis. Delayed domain docking may avoid interdomain misfolding to promote the maturation of multidomain proteins in eukaryotes.
具有多个结构域的蛋白质本质上易于错误折叠，但在核糖体上合成过程中能高效折叠。这在多结构域蛋白质占主导的真核生物中尤为重要。在此，我们试图了解真核生物核糖体如何调节多结构域蛋白质的折叠。我们使用氢-氘交换质谱和冷冻电子显微镜来表征一种模型多结构域蛋白质部分合成中间体的结构和动力学。我们发现，新生的亚结构域在人核糖体上合成过程中逐步折叠，由跨结构域界面的相互作用引导。新生链的构象集合由其无结构的C末端片段调节，这些片段使折叠结构域之间的界面保持动态平衡，直至翻译终止。这与细菌核糖体形成对比，在细菌核糖体上结构域界面早期形成并在合成过程中保持稳定。延迟的结构域对接可能避免结构域间的错误折叠，以促进真核生物中多结构域蛋白质的成熟。
