Throughout translocation, super-domain I will remain relatively unchanged, as it is responsible for binding tightly to the ribosome.

[6][7][8] Super-domain II in the POST state mimics the tRNA molecule of the EF-Tu • GTP • aa-tRNA ternary complex.

[11] As a highly conserved rRNA loop in evolution, the SRL is critical in helping GTPases bind to the ribosome, but is not essential for GTP hydrolysis.

[12] EF-G catalyzes the translocation of the tRNA and mRNA down the ribosome at the end of each round of polypeptide elongation.

[1][13] As a GTPase, EF-G binds to the rotated ribosome near the A site in its GTP-bound state, and hydrolyzes GTP, releasing GDP and inorganic phosphate: The hydrolysis of GTP allows for a large conformational change within EF-G, forcing the A/P tRNA to fully occupy the P site, the P/E tRNA to fully occupy the E site (and exit the ribosome complex), and the mRNA to shift three nucleotides down relative to the ribosome.

The GDP-bound EF-G molecule then dissociates from the complex, leaving another free A-site where the elongation cycle can start again.

A Class I release factor (RF1 or RF2) binds to the stop codon, which induces hydrolysis of the tRNA-peptide bond in the P site, allowing the newly-formed protein to exit the ribosome.

[21][22] However, some bacterial strains have developed resistance to fusidic acid due to point mutations in the fusA gene, which prevents fusidic acid from binding to EF-G.[23][24] EF-G has a complex evolutionary history, with numerous paralogous versions of the factor present in bacteria, suggesting subfunctionalization of different EF-G variants.