Elongation factor 4 (EF4 or LepA) is a highly conserved guanosine triphosphatase found in bacteria and eukaryotic mitochondria and chloroplasts. EF4 functions as a translation factor, which promotes back-translocation of tRNAs on posttranslocational ribosome complexes and competes with elongation factor G for interaction with pretranslocational ribosomes, inhibiting the elongation phase of protein synthesis.
Jiyao W et al.(2023). "The conserved domain database in 2023.",