Practice question

Elongation GTPases divide into two conserved subfamilies based on biochemical function and domain architecture. EF-Tu and eukaryotic eEF1A specialize in delivering aminoacyl-tRNA to the A-site via ternary complex sampling and kinetic proofreading, whereas EF-G and eukaryotic eEF2 constitute translocases responsible for moving tRNA-mRNA through ribosome by GTP-driven conformational changes. eEF2 preserves five-domain architecture of EF-G including G-domain and tRNA-mimic domain IV that inserts into decoding center to prevent back-translocation. EF-G and eEF2 share GTPase motifs and sensitivity to fusidic acid antibiotic, while EF-Ts functions as exchange factor and IF2/eIF5B mediate initiation steps, not homologous to translocases.