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GTP hydrolysis by EF ‐ G synchronizes t RNA movement on small and large ribosomal subunits
Author(s) -
Holtkamp Wolf,
Cunha Carlos E,
Peske Frank,
Konevega Andrey L,
Wintermeyer Wolfgang,
Rodnina Marina V
Publication year - 2014
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/embj.201387465
Subject(s) - 50s , gtp' , biology , ribosome , 30s , transfer rna , biochemistry , elongation factor , gtpase , ef tu , guanosine triphosphate , protein subunit , p site , chromosomal translocation , ribosomal rna , biophysics , microbiology and biotechnology , rna , enzyme , gene
Elongation factor G ( EF ‐ G ) promotes the movement of two tRNA s and the mRNA through the ribosome in each cycle of peptide elongation. During translocation, the tRNA s transiently occupy intermediate positions on both small (30S) and large (50S) ribosomal subunits. How EF ‐ G and GTP hydrolysis control these movements is still unclear. We used fluorescence labels that specifically monitor movements on either 30S or 50S subunits in combination with EF ‐ G mutants and translocation‐specific antibiotics to investigate timing and energetics of translocation. We show that EF ‐ G – GTP facilitates synchronous movements of peptidyl‐ tRNA on the two subunits into an early post‐translocation state, which resembles a chimeric state identified by structural studies. EF ‐ G binding without GTP hydrolysis promotes only partial tRNA movement on the 50S subunit. However, rapid 30S translocation and the concomitant completion of 50S translocation require GTP hydrolysis and a functional domain 4 of EF ‐ G . Our results reveal two distinct modes for utilizing the energy of EF ‐ G binding and GTP hydrolysis and suggest that coupling of GTP hydrolysis to translocation is mediated through rearrangements of the 30S subunit.