Splitting of the Posttermination Ribosome into Subunits by the Concerted Action of RRF and EF-G

• Published in: Molecular cell Vol. 18; no. 6; pp. 675 - 686
• Main Authors: Zavialov, Andrey V., Hauryliuk, Vasili V., Ehrenberg, Måns
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 10-06-2005
• Subjects: Base Sequence; Kinetics; Models, Molecular; Nucleic Acid Conformation; Peptide Elongation Factor G - metabolism; Protein Biosynthesis; Ribosomal Proteins - metabolism; Ribosomes - metabolism; Ribosomes - ultrastructure; Ribosomes/metabolism/ultrastructure; RNA, Messenger - chemistry; RNA, Messenger - metabolism; RNA, Transfer - chemistry; RNA, Transfer - metabolism; Research Support; RNA; Transfer/chemistry/metabolism; Models; Molecular; Messenger/chemistry/metabolism; Non-U.S. Gov't
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/j.molcel.2005.05.016

After peptide release by a class-1 release factor, the ribosomal subunits must be recycled back to initiation. We have demonstrated that the distance between a strong Shine-Dalgarno (SD) sequence and a codon in the P site is crucial for the binding stability of the deacylated tRNA in the P site of the posttermination ribosome and the in-frame maintenance of its mRNA. We show that the elongation factor EF-G and the ribosomal recycling factor RRF split the ribosome into subunits in the absence of initiation factor 3 (IF3) by a mechanism that requires both GTP and GTP hydrolysis. Taking into account that EF-G in the GTP form and RRF bind with positive cooperativity to the free 50S subunit but with negative cooperativity to the 70S ribosome, we suggest a mechanism for ribosome recycling that specifies distinct roles for EF-G, RRF, and IF3.