Reduced puromycin sensitivity of translocated polysomes after the addition of elongation factor 2 and non-hydrolysable GTP analogues.
Treatment of reticulocyte polysomes with elongation factor eEF-2 and GTP led to an increased sensitivity of peptidyl-tRNA for puromycin as a result of the translocation from the ribosomal A-site to the P-site. Upon addition of an excess of the non-hydrolysable GTP analogue, GuoPP[CH2]P, the puromycin sensitivity decreased rapidly. The decrease in sensitivity required high concentrations of eEF-2 with half maximal effect at an eEF-2 concentration of around 1 microM. The data suggest either that peptidyl-tRNA had re-translocated back to the A-site due to the higher affinity of eEF-2 for the pre-translocation than for the post-translocation ribosome, or that the eEF-2-GuoPP[CH2]P complex blocks the peptidyl-transferase activity.
Nilsson
L
L
Department of Cell Biology, Arrhenius Laboratories E5, Stockholm University, Sweden.
Nygård
O
O
D000818:Animals; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D007700:Kinetics; D008954:Models, Biological; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism*; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism*; D011691:Puromycin / Q000378:metabolism / Q000494:pharmacology*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism
D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D011691:Puromycin; D006160:Guanosine Triphosphate