Complete kinetic mechanism for recycling of the bacterial ribosome
2016 (English)In: RNA: A publication of the RNA Society, ISSN 1355-8382, E-ISSN 1469-9001, Vol. 22, no 1, 10-21 p.Article in journal (Refereed) Published
How EF-G and RRF act together to split a post-termination ribosomal complex into its subunits has remained obscure. Here, using stopped-flow experiments with Rayleigh light scattering detection and quench-flow experiments with radio-detection of GTP hydrolysis, we have clarified the kinetic mechanism of ribosome recycling and obtained precise estimates of its kinetic parameters. Ribosome splitting requires that EF-G binds to an already RRF-containing ribosome. EF-G binding to RRF-free ribosomes induces futile rounds of GTP hydrolysis and inhibits ribosome splitting, implying that while RRF is purely an activator of recycling, EF-G acts as both activator and competitive inhibitor of RRF in recycling of the post-termination ribosome. The ribosome splitting rate and the number of GTPs consumed per splitting event depend strongly on the free concentrations of EF-G and RRF. The maximal recycling rate, here estimated as 25 sec(-1), is approached at very high concentrations of EF-G and RRF with RRF in high excess over EF-G. The present in vitro results, suggesting an in vivo ribosome recycling rate of 5 sec(-1), are discussed in the perspective of rapidly growing bacterial cells.
Place, publisher, year, edition, pages
2016. Vol. 22, no 1, 10-21 p.
bacterial ribosome recycling; elongation factor G; ribosome recycling factor; translation rate optimization; protein synthesis
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:uu:diva-258988DOI: 10.1261/rna.053157.115ISI: 000368967600002PubMedID: 26527791OAI: oai:DiVA.org:uu-258988DiVA: diva2:844274
FunderSwedish Research CouncilKnut and Alice Wallenberg Foundation