Reduced puromycin sensitivity of translocated polysomes after the addition of elongation factor 2 and non‐hydrolysable GTP analogues

[摘要]

Treatment of reticulocyte polysomes with elongation factor cEF-2 and GTP led to an increased sensitivity or 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 cEF-2 with half maximal effect at an cEF-2 concentration of around 1 μM. The data suggest either that peptidyl-tRNA had re-translocated back to the A-site due to the higher affinity of cEF-2 for the pre-translocation than for the post-translocation ribosome, or that the cEF-2-GuoPP[CH₂]P complex blocks the peptidyl-transferase activity.

[学科分类] 生物化学/生物物理

[关键词] Elongation factor;Eukaryote;Protein synthesis;Puromycin;Reticulocyte;Translocation;GuoPP[CH2]P;guanosine 5′-[β;-τ-methylene]-triphosphate;cEF;eukaryotic elongation factor;EF;prokaryotic elongation factor