Po Pengse, Delaney Erin, Gamper Howard, Szantai-Kis D Miklos, Speight Lee, Tu LiWei, Kosolapov Andrey, Petersson E James, Hou Ya-Ming, Deutsch Carol
Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
J Mol Biol. 2017 Jun 16;429(12):1873-1888. doi: 10.1016/j.jmb.2017.04.019. Epub 2017 May 5.
All proteins are synthesized by the ribosome, a macromolecular complex that accomplishes the life-sustaining tasks of faithfully decoding mRNA and catalyzing peptide bond formation at the peptidyl transferase center (PTC). The ribosome has evolved an exit tunnel to host the elongating new peptide, protect it from proteolytic digestion, and guide its emergence. It is here that the nascent chain begins to fold. This folding process depends on the rate of translation at the PTC. We report here that besides PTC events, translation kinetics depend on steric constraints on nascent peptide side chains and that confined movements of cramped side chains within and through the tunnel fine-tune elongation rates.
所有蛋白质均由核糖体合成,核糖体是一种大分子复合物,它能完成忠实解码信使核糖核酸(mRNA)以及在肽基转移酶中心(PTC)催化肽键形成这些维持生命的任务。核糖体进化出了一个出口通道来容纳正在延长的新肽链,保护其不被蛋白水解消化,并引导其出现。新生链正是在这里开始折叠。这个折叠过程取决于PTC处的翻译速率。我们在此报告,除了PTC处的事件外,翻译动力学还取决于新生肽侧链的空间限制,并且受限的侧链在通道内以及通过通道的受限运动微调了延伸速率。