Ribosomal protein eL42 contributes to the catalytic activity of the yeast ribosome at the elongation step of translation
Ribosomal protein eL42 contributes to the catalytic activity of the yeast ribosome at the elongation step of translation
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DOI：
10.1016/j.biochi.2018.12.005
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发表时间：
2019-03-01
期刊：
影响因子：
3.9
通讯作者：
Baouz, Soria
中科院分区：
文献类型：
--
作者：
Hountondji, Codjo;Crechet, Jean-Bernard;Baouz, Soria
核糖体蛋白eL42的GGQ小结构域先前已被证明在人类核糖体中与P位点结合的tRNA的CCA臂相接触，这表明该蛋白可能参与催化活性。在此，我们利用粟酒裂殖酵母（S. pombe）细胞证明，eL42的GGQ小结构域及其邻近区域对核糖体功能至关重要。在GGQ小结构域内或其附近含有氨基酸替换的突变型eL42蛋白无法弥补野生型eL42的功能，并且突变型eL42蛋白的表达导致严重的生长缺陷。这些结果表明，eL42中的突变在体内干扰核糖体功能。此外，我们发现与保守的GGQ区域相关的一些突变导致在多聚苯丙氨酸合成和/或相对于嘌呤霉素的肽酰转移酶反应中的活性降低，与野生型核糖体相比。测得Lys - 55/Arg - 55侧链的pK值为6.95，这明显低于Lys或Arg残基的pK值。总之，我们的研究结果表明，eL42通过促进延伸循环过程对80S核糖体的肽酰转移酶活性有贡献。(C) 2018爱思唯尔公司和法国生物化学与分子生物学学会（SFBBM）。版权所有。
The GGQ minidomain of the ribosomal protein eL42 was previously shown to contact the CCA-arm of P-site bound tRNA in human ribosome, indicating a possible involvement of the protein in the catalytic activity. Here, using Schizosaccharomyces pombe (S. pombe) cells, we demonstrate that the GGQ minidomain and neighboring region of eL42 is critical for the ribosomal function. Mutant eL42 proteins containing amino acid substitutions within or adjacent to the GGQ minidomain failed to complement the function of wild-type eL42, and expression of the mutant eL42 proteins led to severe growth defects. These results suggest that the mutations in eL42 interfere with the ribosomal function in vivo. Furthermore, we show that some of the mutations associated with the conserved GGQ region lead to reduced activities in the poly(Phe) synthesis and/or in the peptidyl transferase reaction with respect to puromycin, as compared with those of the wild-type ribosomes. A pK value of 6.95 was measured for the side chain of Lys-55/Arg-55, which is considerably less than that of a Lys or Arg residue. Altogether, our findings suggest that eL42 contributes to the 80S ribosome's peptidyl transferase activity by promoting the course of the elongation cycle. (C) 2018 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.