Identification of two structural elements important for ribosome-dependent GTPase activity of elongation factor 4 (EF4/LepA)
De Laurentiis, Evelina I.
The bacterial translational GTPase EF4/LepA is structurally similar to the canonical elongation factor EF-G. While sharing core structural features with other translational GTPases, the function of EF4 remains unknown. Recent structural data locates the unique C-terminal domain (CTD) of EF4 in proximity to the ribosomal peptidyl transferase center (PTC). To investigate the functional role of EF4’s CTD we have constructed three C-terminal truncation variants.These variants are fully functional with respect to binding mant-GTP and mant-GDP as determined by rapid kinetics, as well as their intrinsic multiple turnover GTPase activity. Furthermore, they are able to form stable complexes with the 70S ribosome and 50S/30S ribosomal sub units.However,successive removal of the C-terminus impairs ribosome-dependent multiple turnover GTPase activity of EF4, which for the full-length protein is very similar to EF-G. Our findings suggest that the last 44 C-terminal amino acids of EF4 form a sub-domain within the C-terminal domain that is important for GTP-dependent function on the ribosome. Additionally, we show that efficient nucleotide hydrolysis by EF4 on the ribosome depends on a conserved histidine (His 81), similar to EF-G and EF-Tu.
Sherpa Romeo green journal. Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) applies
Ribosome , Nucleotide-binding proteins
De Laurentiis, E. I., & Wieden, H.-J. (2015). Identification of two structural elements important for ribosome-dependent GTPase activity of elongation factor 4 (EF4/LepA). Scientific Reports, 5: 8573. DOI:10.1038/srep08573