瑞士苏黎世联邦理工学院的Nenad Ban以及伯尼尔大学的André Schneider等研究人员，合作解析了锥虫中的线粒体核糖体小亚基生成的组装机制。相关论文2019年9月13日发表于国际学术期刊《科学》杂志上。

研究人员报道了布氏锥虫（Trypanosoma brucei）中线粒体核糖体小亚基的组装，其涉及大量因子，并通过组装中间体的形成进行，对此研究人员使用了冷冻电镜进行分析。其中一个是4兆道尔顿大小的复合物，被称为小亚基组合体，研究人员在其中鉴定了34个与未成熟核糖体RNA（rRNA）相互作用并识别其功能重要区域的因子。这一组装通过rRNA的大规模构象变化以及连续掺入线粒体核糖体蛋白得以进行，并为线粒体中核糖体组装过程的复杂性提供了一个实例。

据介绍，线粒体核糖体是大型核糖核蛋白复合物，其合成由线粒体基因组编码的蛋白质。以前的研究已经描述了一个广泛存在的细胞机器用于核糖体的组装，但其仅作用于真核细胞溶质的核糖体。

附：英文原文

Title: Mitoribosomal small subunit biogenesis in trypanosomes involves an extensive assembly machinery

Author: Martin Saurer, David J. F. Ramrath, Moritz Niemann, Salvatore Calderaro, Céline Prange, Simone Mattei, Alain Scaiola, Alexander Leitner, Philipp Bieri, Elke K. Horn, Marc Leibundgut, Daniel Boehringer, André Schneider, Nenad Ban

Issue&Volume: Vol 365, Issue 6458

Abstract: 

Mitochondrial ribosomes (mitoribosomes) are large ribonucleoprotein complexes that synthesize proteins encoded by the mitochondrial genome. An extensive cellular machinery responsible for ribosome assembly has been described only for eukaryotic cytosolic ribosomes. Here we report that the assembly of the small mitoribosomal subunit in Trypanosoma brucei involves a large number of factors and proceeds through the formation of assembly intermediates, which we analyzed by using cryo–electron microscopy. One of them is a 4-megadalton complex, referred to as the small subunit assemblosome, in which we identified 34 factors that interact with immature ribosomal RNA (rRNA) and recognize its functionally important regions. The assembly proceeds through large-scale conformational changes in rRNA coupled with successive incorporation of mitoribosomal proteins, providing an example for the complexity of the ribosomal assembly process in mitochondria.

DOI: 10.1126/science.aaw5570

Source: https://science.sciencemag.org/content/365/6458/1144