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Ribosomal protein eL42 contributes to the catalytic activity of the yeast ribosome at the elongation step of translation
Biochimie ( IF 3.9 ) Pub Date : 2018-12-11 , DOI: 10.1016/j.biochi.2018.12.005
Codjo Hountondji , Jean-Bernard Créchet , Mayo Tanaka , Mieko Suzuki , Jun-ichi Nakayama , Blanche Aguida , Konstantin Bulygin , Jean Cognet , Galina Karpova , Soria Baouz

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.



中文翻译:

核糖体蛋白eL42在翻译的延伸步骤中有助于酵母核糖体的催化活性

先前显示核糖体蛋白eL42的GGQ微型结构域与人核糖体中P位点结合的tRNA的CCA臂接触,表明该蛋白可能参与了催化活性。在这里,我们使用粟酒裂殖酵母S. pombe)细胞,证明GGQ minidomain和eL42的邻近区域对于核糖体功能至关重要。在GGQ微型域内部或附近含有氨基酸取代的突变eL42蛋白无法补充野生型eL42的功能,并且突变eL42蛋白的表达导致严重的生长缺陷。这些结果表明,在eL42突变与核糖体功能造成干扰体内。此外,我们发现,与野生型核糖体相比,与保守的GGQ区相关的某些突变导致针对嘌呤霉素的聚(Phe)合成和/或肽基转移酶反应的活性降低。对Lys-55 / Arg-55的侧链测得的pK值为6.95,远小于Lys或Arg残基的pK值。总之,我们的发现表明,eL42通过促进延长周期的过程而有助于80S核糖体的肽基转移酶活性。

更新日期:2018-12-11
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