Peptide bond formation destabilizes Shine-Dalgarno interaction on the ribosome

摘要

核糖体不在一个mRNA的末端启动转录过程，相反，它们会结合到一 个内部点(Shine-Dalgarno(SD)序列)上，然后单向转位。对断开核 糖体的mRNA和30S部分之间的结合所需的力进行的精确测量显示，在 第一个肽链形成之前，SD序列稳定核糖体-mRNA的相互作用。一旦该 肽链形成，SD序列就不再稳定它。所以，最初肽链的形成是核糖体释 放sD的一个触发因素，而且还可能是允许核糖体开始沿m：RNA运动的 一个重要因素。%The ribosome is a molecular machine that translates the genetic code contained in the messenger RNA into an amino acid sequence through repetitive cycles of transfer RNA selection, peptide bond formation and translocation. Here we demonstrate an optical tweezer assay to measure the rupture force between a single ribosome complex and mRNA. The rupture force was compared between ribosome complexes assembled on an mRNA with and without a strong Shine-Dalgarno (SD) sequence—a sequence found just upstream of the coding region of bacterial mRNAs, involved in translation initiation.