How can elongation factors EF-G and EF-Tu discriminate the functional state of the ribosome using the same binding site?
Elongation factors EF-G and EF-Tu are structural homologues and share near-identical binding sites on the ribosome, which encompass the GTPase-associated centre (GAC) and the sarcin-ricin loop (SRL). The SRL is fixed structure in the ribosome and contacts elongation factors in the vicinity of their GTP-binding site. In contrast, the GAC is mobile and we hypothesize that it interacts with the alpha helix D of the EF-Tu G-domain in the same way as with the alpha helix A of the G'-domain of EF-G. The mutual locations of these helices and GTP-binding sites in the structures of EF-Tu and EF-G are different. Thus, the orientation of the GAC relative to the SRL determines whether EF-G or EF-Tu will bind to the ribosome.
Sergiev
Petr V
PV
Department of Chemistry, Moscow State University, Russia.
Bogdanov
Alexey A
AA
Dontsova
Olga A
OA
D001665:Binding Sites; D004722:Endoribonucleases / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D020653:Peptide Elongation Factor G / Q000737:chemistry* / Q000378:metabolism*; D010444:Peptide Elongation Factor Tu / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D012270:Ribosomes / Q000378:metabolism*
D005656:Fungal Proteins; D020653:Peptide Elongation Factor G; C014801:alpha-sarcin; D004722:Endoribonucleases; D020558:GTP Phosphohydrolases; D010444:Peptide Elongation Factor Tu