This superfamily entry represents the unique C-terminal domain (CTD) of elongation factor 4 (LepA or GUF1 in Saccaromyces), a GTP-binding membrane protein related to EF-G and EF-Tu. LepA is a noncanonical GTPase that promotes the back translocation of tRNAs on the ribosome during the elongation cycle. It is highly conserved and present in bacteria, mitochondria, and chloroplasts PMID:28320876. LepA contains domains that are homologous to EF-G domain I, II, III, V. However, it also contains a C-terminal domain (CTD) that is not homologous to any region in EF-G. The CTD of LepA may play a primary role in back translocation by providing additional binding interactions with a back-translocated tRNA PMID:18362332.

PFAM:PF06421, INTERPRO:IPR013842,DOI:10.1073/pnas.0801308105