a The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience , Newcastle University , Newcastle upon Tyne , England , UK.
b Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Retzius väg 8, Stockholm , Sweden.
RNA Biol. 2017 Dec 2;14(12):1668-1671. doi: 10.1080/15476286.2017.1356551. Epub 2017 Sep 13.
High resolution cryoEM of mammalian mitoribosomes revealed the unexpected presence of mitochondrially encoded tRNA as a structural component of mitochondrial large ribosomal subunit (mt-LSU). Our previously published data identified that only mitochondrial (mt-) tRNA and mt-tRNA can be incorporated into mammalian mt-LSU and within an organism there is no evidence of tissue specific variation. When mt-tRNA is limiting, human mitoribosomes can integrate mt-tRNA instead to generate a translationally competent monosome. Here we discuss the possible reasons for and consequences of the observed plasticity of the structural mt-tRNA integration. We also indicate potential direction for further research that could help our understanding of the mechanistic and evolutionary aspects of this unprecedented system.
哺乳动物线粒体核糖体的高分辨率冷冻电镜显示，出人意料的是，线粒体编码的 tRNA 作为线粒体大亚基（mt-LSU）的结构组成部分存在。我们之前发表的数据表明，只有线粒体（mt-）tRNA 和 mt-tRNA 可以被整合到哺乳动物 mt-LSU 中，而且在一个生物体中没有证据表明存在组织特异性变异。当 mt-tRNA 有限时，人类线粒体核糖体可以整合 mt-tRNA 来产生有翻译能力的单体。在这里，我们讨论了观察到的结构 mt-tRNA 整合的可塑性的可能原因和后果。我们还指出了进一步研究的潜在方向，这有助于我们理解这个前所未有的系统的机制和进化方面。
