Intersubunit movement is required for ribosomal translocation.

摘要: Translocation of tRNA and mRNA during protein synthesis is believed to be coupled structural changes in the ribosome. The “ratchet model,” based on cryo-EM reconstructions ribosome complexes, invokes relative movement 30S 50S ribosomal subunits this process; however, evidence that directly demonstrates a requirement for intersubunit translocation lacking. To address problem, we created an disulfide cross-link restrict potential movement. cross-linked ribosomes were unable carry out polypeptide synthesis; inhibition was completely reversed upon reduction bridge. In vitro assays showed specifically blocked elongation factor G-dependent translocation. These findings show required translocation, accounting universal two-subunit architecture ribosomes.