Institute of Molecular and Cell Biology, University of Tartu, Riia street 23B, 51010, Tartu, Estonia.
Sci Rep. 2020 Jul 15;10(1):11682. doi: 10.1038/s41598-020-68582-2.
Ribosomes are essential macromolecular complexes conducting protein biosynthesis in all domains of life. Cells can have heterogeneous ribosomes, i.e. ribosomes with various ribosomal RNA and ribosomal protein (r-protein) composition. However, the functional importance of heterogeneous ribosomes has remained elusive. One of the possible sources for ribosome heterogeneity is provided by paralogous r-proteins. In E. coli, ribosomal protein bL31 has two paralogs: bL31A encoded by rpmE and bL31B encoded by ykgM. This study investigates phenotypic effects of these ribosomal protein paralogs using bacterial strains expressing only bL31A or bL31B. We show that bL31A confers higher fitness to E. coli under lower temperatures. In addition, bL31A and bL31B have different effects on translation reading frame maintenance and apparent translation processivity in vivo as demonstrated by dual luciferase assay. In general, this study demonstrates that ribosomal protein paralog composition (bL31A versus bL31B) can affect cell growth and translation outcome.
核糖体是所有生命领域进行蛋白质生物合成的必需的大分子复合物。细胞可以具有异质核糖体，即具有不同核糖体 RNA 和核糖体蛋白（r 蛋白）组成的核糖体。然而，异质核糖体的功能重要性仍然难以捉摸。核糖体异质性的一个可能来源是由 paralogous r-proteins 提供的。在大肠杆菌中，核糖体蛋白 bL31 有两个 paralogs：由 rpmE 编码的 bL31A 和由 ykgM 编码的 bL31B。本研究使用仅表达 bL31A 或 bL31B 的细菌菌株来研究这些核糖体蛋白 paralogs 的表型效应。我们表明，bL31A 在较低温度下赋予大肠杆菌更高的适应性。此外，bL31A 和 bL31B 对体内翻译阅读框维持和明显的翻译进程性有不同的影响，这是通过双荧光素酶测定证明的。总的来说，本研究表明核糖体蛋白 paralog 组成（bL31A 与 bL31B）可以影响细胞生长和翻译结果。
