Primary Citation of Related Structures:   5IMQ, 5IMR
PubMed Abstract: 
Elongation factor 4 (EF4) is a member of the family of ribosome-dependent translational GTPase factors, along with elongation factor G and BPI-inducible protein A. Although EF4 is highly conserved in bacterial, mitochondrial, and chloroplast genomes, its exact biological function remains controversial. Here we present the cryo-EM reconstitution of the GTP form of EF4 bound to the ribosome with P and E site tRNAs at 3.8-Å resolution. Interestingly, our structure reveals an unrotated ribosome rather than a clockwise-rotated ribosome, as observed in the presence of EF4-GDP and P site tRNA. In addition, we also observed a counterclockwise-rotated form of the above complex at 5.7-Å resolution. Taken together, our results shed light on the interactions formed between EF4, the ribosome, and the P site tRNA and illuminate the GTPase activation mechanism at previously unresolved detail.
Organizational Affiliation: 
From the Institute of Molecular and Cell Biology, The Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, 138673 Singapore, the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore, and.
the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore, and.
the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore, and the Institute of Structural Biology, Nanyang Technological University, 636921 Singapore.
From the Institute of Molecular and Cell Biology, The Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, 138673 Singapore, the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore, and the Institute of Structural Biology, Nanyang Technological University, 636921 Singapore ygao@ntu.edu.sg.