Post-termination Ribosome Intermediate Acts as the Gateway to Ribosome Recycling

Cell Reports

Arjun Prabhakar¹  Mark C. Capece¹  Joseph D. Puglisi¹  Junhong Choi¹  Alexey Petrov¹ 

[1] Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA;

关键词: ribosome;    translation;    termination;    stop codon;    release factor;    recycling;    RRF;    EF-G;    IF3;    single-molecule fluorescence;   

DOI  :  10.1016/j.celrep.2017.06.028

来源: DOAJ

【 摘 要 】

During termination of translation, the nascent peptide is first released from the ribosome, which must be subsequently disassembled into subunits in a process known as ribosome recycling. In bacteria, termination and recycling are mediated by the translation factors RF, RRF, EF-G, and IF3, but their precise roles have remained unclear. Here, we use single-molecule fluorescence to track the conformation and composition of the ribosome in real time during termination and recycling. Our results show that peptide release by RF induces a rotated ribosomal conformation. RRF binds to this rotated intermediate to form the substrate for EF-G that, in turn, catalyzes GTP-dependent subunit disassembly. After the 50S subunit departs, IF3 releases the deacylated tRNA from the 30S subunit, thus preventing reassembly of the 70S ribosome. Our findings reveal the post-termination rotated state as the crucial intermediate in the transition from termination to recycling.

【 授权许可】

Unknown